21. A and B share certain characteristics of form while differ in their ways of looking at the inner reality and developing a plot.
虽然A和B在形式上有某些共同之处，但是在审视内心世界和展开情节方面却各不相同。
妙笔赏析：两种事物的异同点对比，通过while（然而）连接，形成结构对比；然后通过share和differ一对反义词的运用形成语义对比。
22. Most, if not all, essays are made up of the beginning, the body and the end.
即使不是所有的，至少大多数文章是由开头、正文和结尾组成。
妙笔赏析：if not all经常跟在most, some, part等词后作插入语，起到减缓行文节奏和丰富表达方式的作用。
23. The beginning rouses the reader's interest in and secures his attention to the subject matter of the essay.
这个开头引起了读者对文章主题的兴趣，并保证了读者关注这一主题。
妙笔赏析：本句两短语rouses the reader's interest in和secures his attention to共用一宾语the subject matter of the essay，难度远远大于两个动词共享一宾语，运用巧妙，行文简洁。
24. Proportion is as important to an essay as it is to a painting.
比例之于文章如同它之于绘画一样重要。
妙笔赏析：本句结构为 Sth is as + adj. to A as it is to B (某物之于A如同它之于B一样......); 本结构类似于 A is to B what / as C is to D (A之于B如同C之于D); 前后结构对称，如同一句古诗。此结构的恰当运用有助于增添文采。
25. Foreign trade is beneficial to and indispensable for all nations.
对外贸易不仅有利于各个国家，而且是必不可少的。
妙笔赏析：本句两短语is beneficial to和is indispensable for共用一宾语all nations;运用巧妙，行文简洁。
26. They present their ideas in an impressive and convincing manner.
他们用给人以深刻印象和令人信服的方式展示自己的观点。
妙笔赏析：作者用present、impressive和convincing等正式词汇表现出主语“they”真诚态度。
27. Under one of the trees stood her parents who, while keeping an eye on her, were examining the milk-white blossoms with great interest and admiration.
她的父母站在一棵树下，一边照看着她，一边饶有兴致和满怀赞赏地察看那些乳白色的花朵儿。
妙笔赏析：本句为完全倒装句。主语为her parents,谓语为stood。因为主语后有一who引导的定语从句（一直到句尾），为了避免头重脚轻，固使用倒装句，同时也起到强调地点状语under one of the trees的作用。
28. Repetitions, for instance, lay emphasis on an idea.
比如说，重复强调了一种观点。
妙笔赏析：lay emphasis / stress on“强调”，经典短语，值得学习模仿。
29. Instead of beginning a sentence with a noun or a pronoun as subject, one may well start out with an adverb or an adverb clause.
一个句子可以一个副词或副词性从句开头，而不是以一个名词或代词作主语。
妙笔赏析：本句以一个副词短语开头，“不走寻常路”；其次，本句用两个同义词短语beginn... with和start out with表达相同语义，避免了用词重复，单调。
30. He had no strength to walk, let alone run.
他没有力气走路，更不用说跑了。
妙笔赏析：let alone“更不用说”，“遑论”；近义表达法：to say nothing of, not to mention
参考资料：新浪博客：高考英语提分教练 http://blog.sina.com.cn/firsttest