21. Until then， his family _D_ from him for six months.

　　A didn’t hear B hasn’t been hearing C hasn’t heard D hadn’t heard

　　until then 直到那时。 hear from sb. 收到某人的来信，得到某人的消息。

　　22. The conference _B_ a full week by the time it ends.

　　A must have lasted B will have lasted C would last D has lasted

　　见到介词by引导的时间状语，谓语动词就应是完成时态。

　　24. Physics is _B_ to the science which was called natural philosophy in history.

　　A alike B equivalent C likely D uniform

　　be alike to sb. 对于某人来说均是一样的。 be equivalent to 相当于。

　　All tastes are alike to him. 所有味道对他来说都一样。

　　27. The new appointment of our president _A_ from the very beginning of next semester.

　　A takes effect B takes part C takes place D takes turns

　　semester n. 学期; president n. 大学校长; take effect 生效，发生效力;

　　take part in 参与，参加; take place=happen 发生; takes turn to do sth. 轮流做某事。

　　28. The president made a _A_ speech at the opening ceremony of the sports meeting， which encouraged the sportsmen greatly.

　　A vigorous B tedious C flat D harsh

　　ceremony n. 典礼，仪式;表达在某个典礼上介词用at。 vigorous adj. 强劲有力的，强有力的。

　　harsh adj. 刺耳的，令人不愉快的; flat adj. 平淡无奇的; tedious adj. 冗长无聊的。

　　29. It is useful to be able to predict the extent _C_ which a price change will affect supply and demand. [extent to]

　　A from B with C to D for

　　30. Finding a job in such a big company has always been _D_ his wildest dreams.

　　A under B over C above D beyond

　　beyond one’s wildest dreams 做梦也想不到。

　　31. It is not easy to learn English well， but if you _C_， you will succeed in the end.

　　A hang up B hang about C hang on D hang onto

　　hang on 坚持，继续下去。

　　32. It is reported that _C_ adopted children want to know who their natural parents are.

　　A the most B most of C most D the most of

　　most单独出现的时候有两种词性要考虑：1 adv. 非常;2 adj. 大多数的。

　　the most后面加多音节的形容词或副词构成该句的最高级。

　　most of + 名词，表示这些名词中的大多数。 make the most of 充分利用。