问题
选择题
— Can you imagine what is Jack doing now? He is playing football outside while everyone else is busy in class!
— He his homework, I think.
A．must have finished
B．must finish
C．can’t have finished
D．mustn’t have finished
答案
答案：A
考查情态动词用法。对现在的推测用：情态动词+do/be;对过去的推测用：情态动词+have done/been;
对过去情况的肯定推测用must have done必定做了某事；否定推测用can’t have done不可能做了某事。