题目内容
He __________ everywhere for materials and finally his efforts paid off. The medicine __________ to be very effective.
A. looked; was proved B. explored; was proved
C. sought; has proved D. hunted; was proving
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题目内容
He __________ everywhere for materials and finally his efforts paid off. The medicine __________ to be very effective.
A. looked; was proved B. explored; was proved
C. sought; has proved D. hunted; was proving