finish doing 还是 finish to do
我们知道，英语习惯上说 finish doing sth，不能说 finish to do sth，但是下面这道题的答案却是A，不是C：
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。
(3) 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 to make money 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。”