英语反义疑问句疑惑2YoumusthavebeentotheGreatWall,haven'tyou?3Theymusthavestayedathomelastnight,didn'tthey?这两个反义疑问句的must都表示推测,按理说疑问部分按must后的动词来判

Question

英语反义疑问句疑惑
2 You must have been to the Great Wall,__haven't you__________?
3 They must have stayed at home last night,___didn't they_________?
这两个反义疑问句的must都表示推测,按理说疑问部分按must后的动词来判断用是吧.
可为什么一个用have,一个用did 不应该是都是用have的形式吗?

Answer 1

这种含有表示推测的情态动词句子的反意疑问句,必须去掉情态动词,然后根据句意（包括考查其所带的时间状语等）,进行实际变化.
第二句去掉must后,根据时间状语last night,原句变化为：They stayed at home last night,所以其反意疑问句是：didn't they?
而第一句去掉must后,因为没有具体的时间状语,所以最好变成：You have been to the Great Wall,所以其反意疑问句为：haven't you?