问题补充:
Harrison Ford is thought to be one of the few movie stars as a carpenter before.
A. to work
B. to be working
C. to have worked
D. to have been working
答案:
A. to work
B. to be working
(答案→)C. to have worked
D. to have been working
解析:考查不定式用法。本题中不定式做定语修饰movie stars;因为后面有时间状语before说明这是一个已经完成的动作,故使用不定式的完成时表示一个已经完成的动作。故C正确。