He devoted most of his time to his research believing his hard work wouldsooner or later.

问题补充：

He devoted most of his time to his research, believing his hard work wouldsooner or later.

A. put off

B. take off

C. come off

D. pay off

答案：

A. put off

B. take off

C. come off

(答案→)D. pay off

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