When and where this took place still unknown.A. isB. hasC. wereD. are

发布时间：2020-08-17 07:32:04

When and where this took place      still unknown.
A. is
B. has
C. were
D. are

网友回答

(答案→)A. is
B. has
C. were
D. are
解析：考查主谓一致：句意：这在什么时候什么地方发生的还不知道。主语是单个的主语从句的时候谓语用单数，unknown是形容词，前面用be动词，选A。
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