what's ____on monday?A.happen B.happened C.happening D.has happened 理由?

问题描述:

what's ____on monday?A.happen B.happened C.happening D.has happened 理由?

B 这里的这个what's=what has,所以,肯定知道句子中用的时态是have/has done现在完成时.那么原型是happen,完成时态,就是happened.所以,答案选B