1. Everyone in our class was working hard and doing what we could _______ a good college.
A. enterB. to enter C. enteringD. entered
【陷阱】容易误选A。有的同学一看到空格前的情态动词 could 就断定此处应填动词原形 enter。
【分析】其实正确答案应是B。此句为省略句，即在 could 后省略了动词 do，若把句子补完整应为Everyone in our class was working hard and doing what we could do to enter a good college。即句中的不定式短语(to enter a good college)是用作目的状语的，而不是与情态动词(could)一起构成谓语。请再看类似例句：
(1) They did what they could to comfort her. 他们尽量安慰她。
