1．She came across three children sleeping under a bridge.
A．passed by B．took a notice of C．woke up D．found by chance
2．It seemed incredible that he had been there a week already.
A．right B．obvious C．unbelievable D．unclear
3．He was tempted by the high salary offered by the company.
A．attracted B．taught C．kept D．changed
4．She gets aggressive when she is drunk.
A．worried B．offensive C．sleepy D．anxious
5．I have little information as regards her fitness for the post.
A．at B．with C．about D．from
6．These animals migrate south annually in search of food.
A．explore B．inhabit C．prefer D．travel
7．There was something peculiar in the way he smiles.
A．different B．wrong C．strange D．funny
8．Make sure the table is securely anchored.
A．repaired B．fixed C．cleared D．booked
9．As a politician, he knows how to manipulate public opinion.
A．influence B．express C．divide D．voice
10．He paused, waiting for her to digest the information.
A．withhold B．exchange C．understand D．contact
11．The rules are too rigid to allow for humane error.
A．general B．inflexible C．complex D．direct
12．Rumors began to circulate about his financial problems.
A．spread B．send C．hear D．confirm
13．Come out, or I’ll bust the door down.
A．break B．shut C．set D．beat
14．The police will need to keep a wary eye on this area of town.
A．naked B．blind C．cautious D．private
15．The contract between the two companies will expire soon.
A．shorten B．start C．end D．resume
Kicking the Habit
What is a bad habit? The most common definition is that it is something that we do regularly, almost without thinking about it, and which has some sort of negative consequence. This consequence could affect those around us, or it could affect us personally. Those who deny having bad habits are probably lying. Bad habits are part of what makes us human.
Many early habits, like sucking our thumb, are broken when we are very young. We are either told to stop doing it by our parents, or we consciously or subconsciously observe that others do not have the same habit, and we gradually grow out of it. It is when we intentionally or unintentionally pick up new habits in our later childhood or early adulthood that it becomes a problem. Unless we can break that habit early on, it becomes “programmed” into our brain.
A recent study of human memory suggests that no matter how hard we try to change our habits, it is the old ways that tend to win, especially in situations where we are rushed, stressed or overworked. Habits that we thought we had got rid of can suddenly come back. During the study programme, the researchers showed a group of volunteers several pictures, and gave them words to associate with them. They then showed the volunteers the same pictures again, and gave them new words to associate with them.
A few days later, the volunteers were given a test. The researchers showed them the pictures, and told them to respond with one of the words they had been given for each one. It came as no surprise that their answers were split between the first set of words and the second. Two weeks later, they were given the same test again. This time, most of them only gave the first set of words. They appeared to have completely forgotten the second set.
The study confirms that the responses we learn first are those that remain strongest over time. We may try to change our ways, but after a while, the response that comes to mind first is usually the first one we learned. The more that response is used, the more automatic it becomes and the harder it becomes to respond in any other way.
The study therefore suggests that over time, our bad habits also become automatic, learned behaviour. This is not good news for people who picked up bad habits early in life and now want to change or break them. Even when we try to put new, good intentions into practice, those previously learned habits remain stronger in more automatic, unconscious forms of memory.
16．Boys usually develop bad habits when they are very young.
A．Right B．Wrong C．Not mentioned
17．We can only break bad habits if others tell us to do so.
A．Right B．Wrong C．Not mentioned
18．Bad habits may resume when we are under pressure.
A．Right B．Wrong C．Not mentioned
19．Researchers were surprised by the answers that the volunteers gave in the first test.
A．Right B．Wrong C．Not mentioned
20．The volunteers found the test more difficult when they did it the second time.
A．Right B．Wrong C．Not mentioned
21．The study suggests that it is more difficult to respond to what we learn first.
A．Right B．Wrong C．Not mentioned
22．If we develop bad habits early in life, they are harder to get rid of.
A．Right B．Wrong C．Not mentioned
下面的短文后有2项测试任务：（1）第23 ~ 26题要求从所给的6个选项中为指定段落每段选择1个小标题；（2）第27 ~ 30题要求从所给的6个选项中为每个句子确定一个最佳选项。
Traffic Jams — No End in Sight
1 Traffic congestion affects people throughout the world. Traffic jams cause smog in dozens of cities across both the developed and developing world. In the U.S., commuters spend an average of a full work week each year sitting in traffic, according to the Texas Transportation Institute. While alternative ways of getting around are available, most people still choose their cars because they are looking for convenience, comfort and privacy.
2 The most promising technique for reducing city traffic is called congestion pricing, whereby cities charge a toll to enter certain parts of town at certain times of day. In theory, if the toll is high enough, some drivers will cancel their trips or go by bus or train. And in practice it seems to work: Singapore, London and Stockholm have reduced traffic and pollution in city centers thanks to congestion pricing.
3 Another way to reduce rush hour traffic is for employers to implement flexitime, which lets employees travel to and from work at off-peak traffic times to avoid the rush hour. Those who have to travel during busy times can do their part by sharing cars. Employers can also allow more staff to telecommute (work from home) so as to keep more cars off the road altogether.
4 Some urban planners still believe that the best way to ease traffic congestion is to build more roads, especially roads that can take drivers around or over crowded city streets. But such techniques do not really keep cars off the road; they only accommodate more of them.
5 Other, more forward-thinking, planners know that more and more drivers and cars are taking to the roads every day, and they are unwilling to encourage more private automobiles when public transport is so much better both for people and the environment. For this reason, the American government has decided to spend some $7 billion on helping to increase capacity on public transport systems and upgrade them with more efficient technologies. But environmentalists complain that such funding is tiny compared with the $50 billion being spent on roads and bridges.
23．Paragraph 1 ____
24．Paragraph 2 ____
25．Paragraph 3 ____
26．Paragraph 4 ____
A．Paying to get in
B．A solution which is no solution
C．Changing work practice
D．Closing city centres to traffic
E．Not doing enough
F．A global problem
27．Most American drivers think it convenient to ________.
28．If charged high enough, some drivers may ________ to enter certain parts of town.
29．Building more roads is not an effective way to ________.
30．The U.S. government has planned to ________ updating public transport systems.
A. reduce traffic jams
B．spend more money
E．go by bus
F．encourage more private cars
第一篇 Operation Migration
If you look up at the sky in the early fall in the northern part of North America, you may see groups of birds. These birds are flying south to places where they can find food and warmth for the winter. They are migrating（迁徙）. The young birds usually learn to migrate from their parents. They follow their parents south, in one unusual case, however, the young birds are following something very different. These birds are young whooping cranes, and they are following an airplane!
The young whooping crane is the largest bird that is native to North America. These birds almost disappeared in the 1800s. By 1941, there were only about 20 cranes alive. In the 1970s, people were worried that these creatures were in danger of disappearing completely. As a result, the United States identified whooping cranes as an endangered species that they needed to protect.
Some researchers tried to help. They began to breed whooping cranes in special parks to increase the number of birds. This plan was successful. There were a lot of new baby birds. As the birds became older, the researchers wanted to return them to nature. However, there was a problem: These young birds did not know how to migrate. They needed human help.
In 2001, some people had a creative Idea. They formed an organization called Operation Migration. This group decided to use very light airplanes, instead of birds, to lead the young whooping cranes on their first trip south. They painted each airplane to look like a whooping crane. Even the pilots wore special clothing to make them look like cranes. The cranes began to trust the airplanes, and the plan worked.
Today, planes still lead birds across approximately 1,200 miles (1,931 kilometers), from the United States-Canadian border to the Gulf of Mexico. They leave the birds at different sites. If a trip is successful, the birds can travel on their own in the future. Then, when these birds become parents, they will teach their young to migrate. The people of Operation Migration think this is the only way to maintain the whooping crane population.
Operation Migration works with several other organizations and government institutes. Together, they assist hundreds of cranes each year. However, some experts predict that soon, this won’t be necessary. Thanks to Operation Migration and its partners, the crane population will continue to migrate. Hopefully, they won’t need human help any more.
31．Whopping cranes migrate in winter to
A．raise baby whooping cranes.
B．find warmth and food.
C．get human help.
32．Whopping cranes are native to
C．the Persian Gulf
33．Operation Migration aims to
A．teach adult cranes how to fly.
B．breed cranes in special parks.
C．lead young cranes on their first trip south.
D．transport cranes to the North.
34．The distance covered by the young whooping cranes on their trip south is
35．If Operation Migration is successful, whooping cranes will
A．follow airplanes south every year.
B．live in Canada all year round.
C．be unable to fly back.
D．learn to migrate on their own.
第二篇 “Lucky” Lord Lucan — Alive or Dead
On 8th November 1974 Lord Lucan, a British aristocrat, vanished. The day before, his children’s nanny had been brutally murdered and his wife had been attacked too. To this day the British public are still interested in the murder case because Lucan has never been found. Now, over 30 years later, the police have reopened the case, hoping that new DNA techniques will help solve this murder mystery.
People suspected that "Lucky", as he was called by friends, wanted to kill his wife he no longer lived with. They say that Lucan entered his old house and in the dark, killed the nanny by mistake. His estranged wife heard noises, came downstairs and was also attacked, but managed to escape. Seven months after the murder, a jury concluded that Lucan had killed the nanny.
What happened next is unclear, but there are several theories which fall into one of three categories: he may have killed himself, he could have escaped or he might have been killed. It appears that the night after the murder, "Lucky" borrowed a car and drove it, Lucan’s friend Aspinall said in an interview that he thought Lucan had committed suicide by sinking his boat in the English Channel.
Another version of events says that "Lucky" left the blood-soaked car on the coast and took a ferry to France. He was met there by someone who drove him to safety in another country. However, after a time, his rescuers became worried that they would become involved in the murder too and so Lucan was killed.
A further fascinating theory was made in the book Dead Lucky by Duncan MacLaughlin, a former detective. He believes that Lucan travelled to Goa, India, where he assumed the identity of a Mr. Barry Haplin. Lucan then lived in Goa till his death in 1996．In the end the claim turned out to be a case of mistaken identity. The man who died in 1996 was really Haplin, an ex-schoolteacher turned hippy. So what is the truth about "Lucky"? DNA testing has solved many murder cases, but who knows if it can close the book on this one.
36．British public are still interested in the murder case because
A．the murderer was an aristocrat.
B．the murderer has not been caught
C．the murderer’s DNA has been found.
D．the murderer was a famous man.
37．it was suspected that Lucan killed the nanny because
A．she was cruel to his children.
B．she attacked his wife.
C． she was mistaken for his wife.
D．she stole his car
38．Aspinall thought Lucan killed himself
A．in a car accident.
B．on the night 30 years after the murder.
C．by jumping into the English Channel.
D．by sinking his boat.
39．According to the version in Paragraph 4, Lucan
A．was involved in a murder in France.
B．was caught in another country.
C．met his partners on a ferry.
D．had escaped but was killed later
40．The word "assumed" in the last paragraph means
第三篇 On the Trail of the Honey Badgers
On a recent field trip to the Kalahari Desert, a team of researchers learnt a lot more about honey badgers（獾）. The team employed a local wildlife expert, Kitso Khama, to help them locate and follow the badgers across the desert. Their main aim was to study the badgers’ movements and behaviour as discreetly（谨慎地）as possible, without frightening them away or causing them to change their natural behaviour. They also planned to trap a few and study them close up before releasing them. In view of the animal’s reputation, this was something that even Khama was reluctant to do.
“The problem with honey badgers is they are naturally curious animals, especially when they see something new,” he says. “that, combined with their unpredictable nature, can be a dangerous mixture. If they sense you have food, for example, they won’t be shy about coming right up to you for something to eat. They’re actually quite sociable creatures around humans, but as soon as they feel they might be in danger, they can become extremely vicious（凶恶的）. Fortunately this is rare, but it does happen.”
The research confirmed many things that were already known. As expected, honey badgers ate any creatures they could catch and kill. Even poisonous snakes, feared and avoided by most other animals, were not safe from them. The researchers were surprised, however, by the animal’s fondness for local melons, probably because of their high water content. Previously researchers thought that the animal got all of its liquid requirements from its prey（猎物）. The team also learnt that, contrary to previous research findings, the badgers occasionally formed loose family groups. They were also able to confirm certain results from previous research, including the fat that female badgers never socialized with each other.
Following some of the male badgers was a challenge, since they can cover large distances in a short space of time. Some hunting territories cover more than 500 square kilometers. Although they seem happy to share these territories with other males, there are occasional fights over an important food source, and male badgers can be as aggressive towards each other as they are towards other species.
As the badgers became accustomed to the presence of people, it gave the team the chance to get up close to them without being the subject of the animal’s curiosity — or their sudden aggression. The badgers’ eating patterns, which had been disrupted, returned to normal. It also allowed the team to observe more closely some of the other creatures that form working associations with the honey badger, as these seems to adopt the badgers’ relaxed attitude when near humans.
41．Why did the wildlife experts visit the Kalahari Desert?
A．To find where honey badgers live.
B．To observe how honey badgers behave.
C．To catch some honey badgers for food.
D．To find out why honey badgers have a bad reputation.
42．What does Kitso Khama say about honey badgers?
A．They show interest in things they are not familiar with.
B．They are always looking for food.
C．They do not enjoy human company.
D．It is common for them to attack people.
43．What did the team find out about honey badgers?
A．There were some creatures they did not eat.
B．They were afraid of poisonous creatures.
C．They may get some of the water they needed from fruit.
D．Female badgers did not mix with male badgers.
44．Which of the following is a typical feature of male badgers?
A．They don’t run very quickly.
B．They hunt over a very large area.
C．They defend their territory from other badgers.
D．They are more aggressive than females
45．What happened when honey badgers got used to humans around them?
A．They lost interest in people.
B．They became less aggressive towards other creatures.
C．They started eating more.
D．Other animals started working with them.
The Tough Grass that Sweetens Our Lives
Sugar cane was once a wild grass that grew in New Guinea and was used by local people for roofing their houses and fencing their gardens. Gradually a different variety evolved which contained sucrose and was chewed on for its sweet taste. Over time, sugar cane became a highly valuable commercial plant, grown throughout the world. __________ (46)
Sugar became a vital ingredient in all kinds of things, from confectionery to medicine, and, as the demand for sugar grew, the industry became larger and more profitable. __________ (47) Many crops withered and died, despite growers’ attempts to save them, and there were fears that the health of the plant would continue to deteriorate.
In the 1960s, scientists working in Barbados looked for ways to make the commercial species stronger and more able to resist disease. They experimented with breeding programmes, mixing genes from the wild species of sugar cane, which tends to be tougher, with genes from the more delicate, commercial type. __________ (48) This sugar cane is not yet ready to be sold commercially, but when this happens, it is expected to be incredibly profitable for the industry.
__________ (49) Brazil, which produces one quarter of the world’s sugar, has coordinated an international project under Professor Paulo Arrudo of the Universidade Estaudual de Campinas in Sao Paulo. Teams of experts have worked with him to discover more about which parts of the genetic structure of the plant are important for the production of sugar and its overall health.
Despite all the research, however, we still do not fully understand how the genes function in sugar cane. __________ (50) This gene is particularly exciting because it makes the plant resistant to rust, a disease which probably originated in India, but is now capable of infecting sugar cane across the world. Scientists believe they will eventually be able to grow a plant which cannot be destroyed by rust.
A．Eventually, a commercial plant was developed which was 5 percent sweeter than before, but also much stronger and less likely to die from disease.
B．Since the 1960s, scientists have been analysing the mysteries of the sugar cane’s genetic code.
C．One major gene has been identified by Dr Angelique D’Hont and her team in Montpelier, France.
D．The majority of the world’s sugar now comes from this particular commercial species.
E．Sugar cane was now much vigorous and the supply of sugar is therefore more guaranteed.
F．Unfortunately, however, the plant started to become weaker and more prone to disease.
Teaching and Learning
Many teachers believe that the responsibilities for learning lie with the student. If a long reading assignment is given, instructors expect students to be familiar with the ___51___ in the reading even if they do not discuss it in class or take an examination. The ___52___ student is considered to be one who is motivated to learn for the sake of ___53___, not the one interested only in getting high grades. Sometimes homework is returned ___54___ brief written comments but without a grade. Even if a grade is not given, the student is ___55___ for learning the material assigned. When research is ___56___, the professor expects the student to take it actively and to complete it with ___57___ guidance. It is the student's responsibility to find books, magazines, and articles in the library. Professors do not have the time to explain ___58___ a university library works; they expect students ___59___ graduate students to exhaust the reference ___60___ in the library. Professors will help students who need it, but ___61___ that their students should not be ___62___ dependent on them. In the United Stats professors have many other duties ___63___ teaching, such as administrative or research work. Therefore, the time that a professor can spend with a student outside of class is ___64__. If a student has problems with classroom work, the student should either ___65___ a professor during office hours or make an appointment.
51. A) careful B) happy C) familiar D) pleased
52. A) need B) take C) develop D) finish
53. A) tested B) recognized C) assessed D) considered
54. A) grades B) levels C) degrees D) hopes
55. A) comments B) tasks C) declarations D) questions
56. A) anxious B) responsible C) concerned D) eager
57. A) completed B) designed C) learned D) assigned
58. A) guidance B) requirement C) effort D) evidence
59. A) wonder B) inquire C) explain D) speculate
60. A) inner B) reference C) personal D) natural
61. A) even B) but C) thus D) and
62. A) keen B) energetic C) active D) dependent
63. A) duties B) opportunities C) preferences D) points
64. A) for B) over C) with D) along
65. A) approach B) trouble C) select D) catch
1D 2C 3A 4B 5C
6D 7C 8B 9A 10C
11B 12D 13A 14C 15C
16C 17B 18A 19B 20C
21B 22A 23F 24A 25C
26B 27C 28E 29A 30B
31B 32D 33C 34B 35D
36B 37C 38D 39D 40B
41B 42A 43C 44B 45A
46D 47F 48A 49B 50C
51C 52B 53D 54A 55A
56B 57D 58A 59C 60B
61B 62D 63A 64C 65A
第一部分：第1 ~ 15题，每题1分，15分；
第二部分：第16 ~ 22题，每题1分，7分；
第三部分：第23 ~ 30题，每题1分，8分；
第四部分：第31 ~ 45题，每题3分，45分；
第五部分：第46 ~ 50题，每题2分，10分；
第六部分：第51 ~ 65题，每题1分，15分。
1 D come across是固定搭配，意思是“偶遇，碰巧发现”，因此选择D选项。pass by“路过”，take a notice of“注意到”，wake up“醒来”。
2 C incredible意为“难以置信的”，与unbelievable同义。obvious“明显的”，unclear“不明的”。
3 A tempt“吸引，诱惑”，此处为被动态，句子意思为：他被这家公司开出的高额薪水吸引了。A选项符合句义。
4 B aggressive意为“好斗的，富于攻击性的”，与offensive相近，如：Men tend to be more aggressive than women.男性往往比女性更具有攻击性。Knives of any sort are classed as offensive weapons.任何刀具都属于攻击性武器。worried“担心的”，sleepy“困倦的”，anxious“焦急的”。
5 C as regards是固定搭配，意思是“关于”，如：There is no problem as regards the financial arrangements.资金筹备方面毫无问题。
6 D migrate的意思是“迁徙”，travel除了常见的“旅行”意思外，还有“行进”的意思，如：Supersonic planes can travel faster than the speed of sound.超音速飞机的速度比音速快。在这里可作同义替换。explore“探索”，inhabit“栖息，居住”，prefer“更喜欢”。
7 C peculiar“奇怪的，古怪的”，如：She has the most peculiar ideas.她的想法非常古怪，因此选择C。
8 B anchor本义是“锚，下锚”，此处转义为“固定住”，与选项B同义。repair“修理”，clear“清除”，book“预订”。
9 A manipulate意为“操纵，控制”，句子的意思是：作为一个政治家，他知道如何左右公共舆论。influence的意思是“影响”，在这里可替换。express“表达”。
10 C digest本义是“消化”，可转义为“理解（知识、信息）”，在句中可与understand互换。withhold“保留，隐瞒”；exchange“交换”；contact“联系”。
11 B rigid“僵硬的，固定的，顽固的”，与inflexible同义。
12 D circulate做不及物动词，意思是“传播，流通”，如：We should often open the windows to allow the air to circulate.我们应当经常打开窗户以使空气流通。句子的意思是：关于他的财政问题的流言开始传开。
13 A bust“使爆裂”，句子的意思是：快点，不然我就破门而入了。这里与break同义。
14 C wary“谨慎的，机警的”，与cautious同义。naked“裸体的”，blind“盲的”，private“私人的”。
15 C expire“期满，终止”。resume是“重新开始”。
16 C 文中提到人们的坏习惯是从很小的时候就开始出现了，但并没有提到性别对坏习惯形成的影响。
17 B 文章第二段介绍了停止坏习惯的几种途径，一是父母阻止，二是我们观察到别人的行为从而改变自己的行为，因此题干中的说法是错误的。
18 A 第三段讲到当我们压力大的时候，旧的坏习惯就会卷土重来。
19 B 第四段中提到It came as no surprise that…表示结果在调查者的意料之中。
20 C 文中只提到更多的受试者在第二次测试中选择了第一组也就是先记住的词汇，并没有讲他们对题目难度的感受。
21 B 调查显示人们更容易记住先学到的东西。
22 A 文中最后两段都是在讲小时候坏习惯是根深蒂固的，即使努力摆脱，也常常容易回到旧轨道上去。
23 F 第一段讲述的是交通拥堵是全世界的一大问题。
24 A 第二段讲述了控制交通量的一个方法，即对在某个时间进人某个区域的车辆征收费
25 C 事三段讲述的是另一个控制交通量的方法，即实行灵活上班时间，允许雇员避开交通高峰出行。
26 B 第四段讲述的是部分城市规划者认为应该建造更多的公路，不过这种方法并不会减少交通量，而是能容纳更多的车辆。
27 C 第一段最后一句：While alternative ways of getting around are available, most people still choose their cars because they are looking for convenience, comfort and privacy.由此可知人们认为开车比较方便。
28 E 第二段第二句：In theory, if the toll is high enough, some drivers will cancel their trips or go by bus or train・由此可知答案为E。
29 A 第四段第二句：But such techniques do not really keep cars off the road..，由此可知建造赶多公路并不能减少交通堵塞。
30 B 第五段第二句：For this reason, the American government has decided to spend some$ 7 billion on helping to increase capacity on public-transport systems and upgrade them with more efficient technologies.美国政府决定增加投人升级公共交通系统。由此可知答案为B。
31 B 第一段第二句：These birds are flying south to places where they can find food and warmth for the winter.因此选B0
32 D 第二段第一句：The whooping crane is the largest bird that is native to North America.因此选D0
33 C 第四段第三句：This group decided to use very light airplanes, instead of birds, to lead the young whooping cranes on their first trip south.因此选C0
34 B 第五段第一句：Today, planes still lead birds across approximately 1, 200 miles…因此选B0
35 D 由最后一段可知，如果该计划成功的话，小美洲鹤就能学会自己迁徙，这也是这一计划的目的。
36 B 由第一段第三句：To this day the British public are still interested in the murder case be- cause Lucan has never been found.可选出答案为B0
37 C 第二段讲了人们对当时情况的猜测。They say that Lucan entered his old house and in the dark, killed the nanny by mistake.保姆是被错认成Lucan的妻子才被杀害的。
38 D 第三段最后一句：Lucan’s friend Aspinall said in an interview that he thought Lucan had committed suicide by sinking his boat in the English Channel.
39 D 第四段讲述了一种版本的猜测，即Lucan被救之后又被杀害。
40 B 句子的意思是Lucan假冒了另一个人的身份，assume有“冒充”的意思，在四个选项里面，take on an identity同样有“冒充身份”的意思，其他三个词都不能与identity搭配。
41 B 第一段第三句：Their aim was to study the badgers' movements and behaviour as discreetly（谨慎地）as possible.可推断出此次调查的目的是了解獾的习性。
42 A 第二段讲述了Khama对獾的评价，即它们有很强的好奇心。
43 C 由第三段可知，獾对当地的西瓜很感兴趣，而西瓜含水量很高，它们吃西瓜是为了得到水分。獾通常会吃它们所能抓到的任何动物，连毒蛇也不怕，因此A、B选项错误。獾会组成松散的家庭，因此可排除D项。
44 B 第四段讲了雄性獾的特征，它们能在短时间内行进很长的距离，因此B项正确。它们乐意同其他雄性獾分享领地，因此C错误。文中并没有提到它们在好斗性方面同雌性獾的区别，因此排除D项。
45 A 最后一段第一句：As the badgers became accustomed to the presence of people, it gave the team the chance to get up close to them without being the subject of the animals' curiosity - or their sudden aggression.獾在习惯人的存在之后兴趣就不那么浓厚了。
46 D 句子前面讲述甘蔗的发展，后面讲的是糖的情况，因此这里选D项合适，D项中的this particular commercial species也与前文呼应。
47 F 前文讲对糖的需求越来越高，后文讲许多植株枯萎死亡了，因此所缺的句子应该是转折的句子，F符合条件。
48 A 前文讲到科学家想通过实验培育出更强壮的甘蔗品种，后面讲这有可能为这一产业带来高额利润，因此所缺句子应该是讲科学家培育出了新品种。
49 B 后文讲巴西是世界上白糖生产大国，它与一个国际计划合作，研究甘蔗的基因结构。B项讲的是科学家正在分析甘蔗的基因序列，符合题意。
50 C 前文讲到我们现在还没完全了解甘蔗中的基因，后文提到this gene，是特指前文中的一种基因，C选项中提到科学家找出了一种基因，与题意相符。
51 C 老师希望学生对要求读的东西熟悉。
52 B take an examination是固定搭配，意为“参加考试”。
53 D 为了学习本身而学习的人被认为是好学生。consider“认为”，test“测试”，recognize“认可”，assess“评估”。
54 A grade“评级”，指对学生的表现作出的评价，学生们根据表现得到A、B、C、D或其他等级的评价；level“水平”，是指一个人的内在水平，不因为外部评价而改变；degree“程度”。
55 A 学生的作业得到老师的评论。comment意为“评论”，declaration“宣言”。
56 B K. B. D选项均能和for搭配。句子意思是：即使没有评级，学生也应该完成所布置的任务。be responsible for something意为“应当做某事”，符合题意。
57 D assign“布置（任务）”，也可以从前文得到线索。
58 A 教师希望学生尽量独立完成任务。guidance“指导”，minimum guidance“尽量少的指导”，就是尽量独立完成。requirement“要求”，effort“努力”，evidence“证据”。
59 C 教授没时间向学生们解释图书馆怎样使用。wonder“怀疑”，inquire“询问”，speculate“查询”。
60 B 意为“图书馆内的参考资料”。
61 B 前后两个句子的意思相反，因此所填入的词应该是表转折的but。
62 D 教授不希望学生过分依赖图书馆。dependent on“依赖的”，其他几个选项意思都不符。
63 A 在美国，教授除了教学之外还有许多其他事情要做。
64 C spend time with someone“与某人在一起做事”，其他几个选项和原文不能搭配。
65 A approach“接近”，句意是：如果学生对课堂作业有疑问，他可以在老师办公时间去找老师或者提前预约。