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
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C解析试题分析：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。考点：考查不定式用法点评：不定式的完成式表示在谓语动词之前已经完成。