He _writing the paper now.He hadn't written a single word when i left him ten minutes ago.
问题描述：
He _writing the paper now.He hadn't written a single word when i left him ten minutes ago.
A.shouldn't be B.can't have finished C.can't be D.mustn't have finished
我选的是A 答案为什么是b
答
can't have finished
1.虚拟语气表猜测,否定式can't 【而不用shouldn't】
2.have finished 现在完成时表完成.
这句要表达的意思是,他现在一定还没有完成作业,十分钟前,当我离开他的时候,他还没有动笔.