Madame Curie is believed radium.A. discoveringB. having discoveredC. to have discoveredD.

发布时间：2020-08-16 17:08:50

Madame Curie is believed      radium.
A. discovering
B. having discovered
C. to have discovered
D. to discover

网友回答

A. discovering
B. having discovered
(答案→)C. to have discovered
D. to discover
解析：句型sb be believed to do 据说… 。 根据语境可知discover是已发生的动作所以用不定式的完成式。 据说居里夫人发现了镭。 选C
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