Group13 In, Il, Im, Ir-not, un
“不；非”
impunity
n. 不受处罚　
As a result of stricter enforcement, speeders are no longer able to break the law with impunity.
由于更严格执行法律的结果，超速者已不可能违法而不受罚。
ingratitude
n. 忘恩负义　
Alice refused to let me see her notes, despite the fact that I have always lent her mine. did you ever hear of such ingratitude?
艾丽斯拒绝让我看她的笔记，尽管我总是把我的借给她。你听过如此忘恩负义的事吗？
illegible
adj. 难读的；难认的　
I could read most of the signatures, but a few were illegible.
我可以认出大部份的签名，但有一些不好认
illiterate
adj. 不识字的　
The new nation undertook to teach its illiterate citizens to read and write.
那个新成立的国家着手教导不识字的国民读与写。
illogical
adj. 不合逻辑的；不合常理的　
It is illogical to vote for a candidate whom you have no faith in.
将选票投给一位你没信心的候选人是不合常理的。
immaculate
adj. 无污点的；清静的　
Nearly every soap manufacturer claims his product will make dirty linens immaculate.
几乎每一个肥皂制造商都宣称他的产品可以洗净肮脏的亚麻布。
immature
adj. 不成熟的　
Don't use such baby talk! People will think you are mentally immature.
别说这么孩子气的话！别人会以为你心智未成熟。
inaccessible
adj. 不能到达的　
For most of the year, the Eskimo settlements in northern Quebec are inaccessible, except by air.
一年中大部份的时间，除了搭飞机外，是到不了北魁北克的爱斯墓康居留地的。
incessant
adj. 　不断的　
It is almost impossible to cross our street during the rush hour because of the incessant flow of traffic.
高峰时间车辆川流不息，很难越过我们那条街。
inflexible
adj. 强硬的，不屈的　
No compromise is possible when both sides remain inflexible.
当双方态度都很强硬时，是不可能达成协议的。
inhospitable
adj. 待客不亲切的；冷淡的　
When the visitors come to our school, we should make them feel at home;otherwise they will think we are inhospitable.
当访客来到我们学校时，应该让他们有宾至如归的感觉，否则他们会认为我们待客不亲切。
insoluble
adj. 1. 不能解决的　2. 不溶解的　
Scientists are finding solutions to many problems that up to now were insoluble.
科学家正在为许多至今尚无解答的问题寻找答案。
Salt dissolves in water, but sand is insoluble.
盐在水中会溶解，而沙就不溶解。
irreconcilable
adj. 对立的；不能和解的　
After Romeo and Juliet died, their families, who had been irreconcilable enemies, became friends.
罗密欧与朱丽叶死后，他们原本相对立的家族，变成了朋友。
irrelevant
adj. 不相干的；不切题的　
Stick to the topic;don't make irrelevant remarks.
坚守主题；不要说一些不相干的话。
irrevocable
adj. 无法挽回的；不能撤销的　
When the umpire says you are out, it is useless to argue because his decision is irrevocable.
裁判说你出局时，争辩是没有用的，因为他的决定不可能撤销。