The extra room very useful when we had visitors.A. was provedB. provedC. has been provedD

发布时间：2020-08-16 21:03:49

The extra room      very useful when we had visitors.
A. was proved
B. proved
C. has been proved
D. has proved

网友回答

A. was proved
(答案→)B. proved
C. has been proved
D. has proved
解析：系动词用法。系动词prove是没有被动语态的。“Prove +形容词”构成系表结构。
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