请看下面一道题:This is the very work that I must finish _________ her.
A. to help                 B. help                    C. helping                  D. helped

有的同学一看到动词 finish,便断定其后空格肯定填动名词,即断定此题答案选C。其实错了,正确答案应是 A。不错,finish 后接动词作宾语时,该动词要用动名词,而不用不定式,但是本句空格处填的动词help 并不是 finish 的宾语,正确的句子分析是:that I must finish 是修饰名词 the very work 的定语从句,finish 的宾语是引导该定语从句的关系代词 that,其后的不定式 to help her 是目的状语。全句意为“为了帮助她,这就是我们必须要完成的工作。”请再看类似例题:

(1) What the children enjoy _________ to play outside.
A. being                     B. to be                    C. is                          D. are
答案选C,而不选A。what the children enjoy 是主语从句,空格处填的 is 为谓语动词。

(2) What else would you mind _________ money?
A. make                      B. making                 C. to make                 D. made
答案选C,而不选B。动词mind 的宾语是句首的疑问词 what,而不是其后的动词 make;不定式用作目的状语。

(3) Nothing that he suggested _________ useful.
A. prove                     B. proved                   C. proving                 D. to prove
答案选B,而不选C。句子主语是 nothing;that he suggested 是修饰主语的定语从句,suggested 的宾语是引导该定语从句的关系代词 that,而不是其后的动词;句子谓语是 proved。全句意为“他建议的情况没有一条是有用的。”