用must表推測的反意疑問句的有關用法
1）對現(xiàn)在情況的推測,問句部分用主動詞（do,be)一般現(xiàn)在時的適當形式.若是現(xiàn)在進行時,問句部分用現(xiàn)在進行時的適當形式表示.若是there be結(jié)構(gòu),問句用isn't/aren't there.如：
1)He must be there,isn't he?
2)He must have a big family,doesn't he?
3)He must be waiting outside,isn't he?
4)There must be some students in the room,aren't there?
2）對已發(fā)生的過去情況的推測,若陳述句謂語部分有“must have done”,而且有表示過去的時間狀語,問句部分用didn't；若沒有表示過去的時間狀語,問句部分用haven't或hasn't.如：
1)They must have gone there last night,didn't they?
2)They must have arrived by now,haven't they?（根據(jù)by now來判斷）
3)They must have been to the Great Wall,haven't they?
3）若是被動,應按被動結(jié)構(gòu)來處理.如：
1)The room must have been cleaned yesterday,wasn't it?
2)The room must have been cleaned,hasn't it?
4）若句中有表示過去完成時的時間狀語,問句部分應用hadn't.如:
They must have learnt 5000 English words by the end of last term,hadn't they?
(本題中must表推測,如果將它去掉,還原為真實句就是They had learnt 5000 English words by the end of last term.因此,反意問句是hadn't）