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，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
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. 某人来说均是一样的。 be equivalent to 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，效力;
take part in ，参加; take place=happen ; 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. 强劲的，强的。
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。
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 ，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单独的时候有两种词性要考虑：1 adv. 非常;2 adj. 大多数的。
most of + 名词，表示名词中的大多数。 make the most of 。