例题4(1997年8月考题) Unlike fossil fuels, which can be used only once, wind and solar power _____of energy.
(A) for renewable sources
(B) the sources are renewable
(C) are renewable sources
(D) renewable sources
这里，句子的主干应该是wind and solar power____ of energy。Unlike fossil fuels表示比较，做状语。而which引导的从句which can be used only once修饰fossil fuels。我们将4个选项分别代入句子主干的空格中，得(A) wind and solar power for renewable sources of energy选项A没有主语，即没有完整的主谓结构。(B) wind and solar power the sources are renewable of energy很明显，这也不能构成一个完整的有意义的句子。(C) wind and solar power are renewable sources of energy这个选项最合适，因为主谓齐全，而且以名词sources结尾，让介词短语of energy修饰。(D) wind and solar power renewable sources of energy很明显，这也不能构成一个完整的主谓结构。所以，正确答案是C
例题5(1997年8月考题) Today _____ of the Earth live on a very small percentage of the Earth's land surface.
(A) about two-thirds populated
(B) the population is about two-thirds
(C) about two-thirds of the population
(D) of about two-thirds the population is
首先，分析句子结构。根据句子的大意，动词live应该是主句的谓语动词。空格填入的应该是句子的主语，而a very small percentage of修饰限定the Earth's land surface。我们简化这个句子，得出句子主干_____ live on the Earth's land surface。空格内应该填入名词或者名词短语。4个选项中，只有C是明显的名词短语，代入后也符合句意。选项A中的populated不论是做定语还是谓语都不符合句意。而选项B和D都是带有助动词的主谓结构，当然不能填入只缺主语的句子中。所以，正确答案是C。
例题6(1997年8月考题) Following the guidelines for speaking and voting established by the book Robert's Rules of Order, _____during meetings.
(A) and avoid large decision-making organizations' procedural confusion
(B) large decision-making organizations avoid procedural confusion
(C) is procedural confusion avoided by large decision-making organizations
(D) are avoiding procedural confusion in large decision-making organizations
首先，我们分析following以后空格以前句子的成分。其中的established by the book Robert's Rules of Order和for speaking and voting都修饰the guideline。所以，我们可以将空格前的成分简化为following the guidelines。那么这时，原句成为Following the guidelines, _____ during meeting.和例题3一样，following the guidelines不是做定语(伴随状语)就是做谓语。如果它做定语，后面必须带自然语序的主谓结构；如果它做谓语，后面必须带倒装的主谓结构。
由此，我们排除带有and的选项A。根据句意(guidelines和confusion的意思)我们又可以排除选项C。这时，我们只剩下选项B和D。选项D是主谓倒装的结构，填入后主语应该是avoiding procedural confusion，谓语动词是are。很明显，avoiding procedural confusion后应跟单数谓语动词。所以D也错，只有B才可能是正确答案。代入句中，符合句意。
例题7(1997年8月考题) Because it was so closely related to communication, _____ art form to develop.
(A) drawing was probably the earliest
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