问题
选择题
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
答案
答案：B
考查情态动词。“can’t have + 过去分词”表示对过去情况的可能性推测，此处意为“不可能已完成”。