核心问题
These proposals sought to place greater restrictions on the use and copying of digital information than ____ in traditional media. A. exist B. exists C. existing D. to exist(全国研考,99-10)
王长喜教授主编《英语试题名家解析 2000 版》(中国人民大学出版社,1999,P.200)对上题作了如下解析：
“答案为[D]。本题要考查比较从句的用法。本句中的两个被比较项是句子中的两个动词的不定式形式，即空白处要填入的部分必须和 to place 是并列的结构。很明显，这样的动词不定式结构只能是[D]项 to exist”。请问正确答案是[D]吗？
词典解答
正确答案是[A]exist。要理解这个句子，必须搞清 than 的用法。最简单明了的方法是把 than 看作是关系代词，引导定语从句，它在定语从句中作主语，其先行词是 restrictions。另一派英语语法学家则把 than 看作是连词，引导比较状语从句，在这里可以理解为省略了 the restrictions which 或者 those which。不管如何解释，exist 都被看作是从句的谓语动词（见 than ）。由此可以证明选[D]to exist 是错误的。
[句意]这些提议要求在使用和复制数字信息时采用比传统媒体更加严格的限制。请做下面的英语试题：
- He often sat in a small bar drinking considerably more than _. A. he was in good health B. his health was good
than did it 1480 C. his good health D. was good for his health(全国六级,95.6-52)
- The project requires more labor than ____ because it is extremely difficult. A. has been put in B. have been put in C. being put in D. to be put in(全国研考,92-28)