She is said in the United States for four years before she came back to work in our compan

She is said in the United States for four years before she came back to work in our company.
A. to study
B. to be studying
C. to have studied
D. studying

A. to studyB. to be studying(答案→)C. to have studiedD. studying解析：常用句型 sth/sb is said to do ....据说。。。题中出现了for four years 说明要用完成时。

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