【问】 Mark Twain is representative post-Civil War authors because of his place ofeducation， and (TOEFL，84. 5)
 我看不出上面的句子有什么错误。
 【答】 英语对于造句有一个要求：结构平行或曰结构对称——当两个或两个以上的同等成份(主语、谓语、宾语、表语、定语、状语、宾语补足语等)并列时，要求它们的词性或结构相同，即名词对名词、形容词对形容词、副词对副词、动词不定式对动词不定式，介词短语对介词短语等等，不一而足。拿上面的句子来说，how he wrote在结构上，应是because of的宾语，与hisplace of birth和education处于同等的语法地位，因此，应当使用词性相同的词项：名词短语。故应将how he wrote改为the way he wrote或his writing style。请看下面实例中的结构平行(结构对称)：
 1. You may either[stand up] or[sit down]. (CGEL)
 你可以站起来，也可以坐下。
 2. Sam neither[has long hair]，nor[wears jeans]. (CGEL)
 萨姆既没有留长发，也没有穿牛仔服。
 3. He didn’t come[to help]，but [to hinder us]. (CGEL)
 他不是来帮助我们的，而是来阻碍我们的。
 4. They not only[broke into his office]，but(also)[tore up his manuscripts]. (CGEL)
 他们不仅闯进了他的办公室，而且还撕碎了他的手稿。
 5. There is always a gap between[what we say] and[what we do]. (TOEFL，74. 3)
 在我们所说的和我们所做的之间总有些差距。
 托福考生应注意，结构平行是托福试题经常考核的项目，应熟练掌握。请做下面的托福题来检查自己对结构平行这一语言点的理解程度：
 1. The replacement and_________represent a sizable portion of Yale University's $ 19 mil-lion library budget.
 A. old books need upkeep B. to keep up old books
 C. old books keep up D. upkeep of old books(TOEFL，92. 7)
 2. Jimmy Davis was amateur country music singer， Louisiana and
 3. Population growth_______ the economic growth of a country as well as be affected by it.
 A. can affect B. is affecting C. affects D. affecting(TOEFL，90. 9)
 4. The barnacle has been a shrimplike animal stands on its head to alimestone house and food its mouth with its feet. (TOEFL，92. 7)
 5. The Hawaiian coastline is bordered by many coral reefs，some living，but ____ dead.A. most of them B. most of their
 C. others are D. the rest are being
 6. Along the rocky New England coast are small areas of sand and gravel beach，some cre-ated from glacial debris，____ by the action of ocean storms.
 A. upbuilding others B. others build up
 C. others built up D. built up others(TOEFL，84.5)
 7. In her writing，Elinor Wylie often dealt with her own personality as it was，rather than
 A. as others defined it B. others’ definitions
 C. its definition by others D. it was defined by others(TOEFL，81.11)
 8. Chemistry is the science of substances____the science of energy.
 A. is physics B. or physics
 C. how physics D. and physics is(TOEFL，85. 11)
 9. X-ray photographs are widely used in industry to test and in inspecting materials andparts. (TOEFL.82.1)
 10. A professional wine taster must rely on taste，sight，and smelling to determinethe quality of a wine. (TOEFL，82.1)
 11. Industrial designers try to make products attraction，efficient，and safe. (TOEFL，82.8)