21.Companies are struggling to find the right ______ between supply and demand， but it is no easy task. A. equation B. formula C. balance D. pattern

正确答案：C

答案解析：参考译文：公司在努力寻找供给和需求之间正确的平衡，但这并不是一个简单的任务。

equation：n. 相等，等式formula：n. 公式，程式;准则，方案balance：n. 平衡，差额vi. 平衡，相等vt. 称，权衡，比较，使平衡，结算，抵消pattern：n. 图案，模范，榜样;型，式样;样品;图样vt. 摹制，仿造;以图案装饰

22.Mass advertising helped to ______ the emphasis from the production of goods to their consumption. A. vary B. shift C. lay D. moderate

正确答案：B

答案解析：参考译文：大规模广告宣传，使重点从商品的生产转移到商品的消费上。

vary：vt. 改变，使多样化vi. 变化，不同，违反shift：n. 移位，变化，移动，轮班，手段，办法vt. 替换，转移，改变，移转，推卸，变速vi. 转换lay：vt. 放，搁;下;铺设，敷设，砌;把…压平，使倒下;使处于某种状态;铺，涂;布置moderate：a. 适度的，稳健的，中等的，节制的vt. 节制，使稳定，使缓和vi. 变缓和

23.His illness accounts ______ his absence from class. A. to B. for C. with D. about

正确答案：B

答案解析：account for表示：是……的原因/理由。

24.I don't feel like ______ anything now. A. to eat B. eating C. eaten D. eat

正确答案：B

答案解析："feel like+doing sth."，表示"想做某事"，后面只能跟动名词形式。

25.Man's life is often compared ______ a candle. A. to B. for C. about D. into

正确答案：A

答案解析：be compared to：…被比喻为…。句意：人生常被喻为蜡烛。

26.To our surprise， the whole story was ______ by a poor old lady. A. discovered B. invented C. found D. searched

正确答案：B

答案解析：本题考查词义的辨析。discovered 发现;invented 创作，虚构，发明。

27.I prefer ______ yesterday， but I had to attend a meeting. A. to come B. to have come C. come D. came

正确答案：B

答案解析：prefer to do sth. 宁愿做某事

28.The ______ he worked， the more progress he made. A. hard B. harder C. harden D. hardly

正确答案：B

答案解析：译文：他工作越努力，进步越大。本题考查"the+比较级……，the +比较级……"结构，表示"越……就越……"前者是状语从句，后者是主句。

29.Jane walked out of the house without ______ a word to her mother. A. as little as B. so much as C. as few as D. so many as

正确答案：B

答案解析：固定搭配。…not so much as…(=not even)甚至于…，连…也不…，根据这个结构应该选B.

30.The leaders of the five countries emphasized that any actions they take concerning the peace of the area should conform ______ their joint statement. A. with B. to C. about D. in

正确答案：B

答案解析：conform to表示"遵照，符合"的意思。