Definition: used to show that you think something is very likely or certain to be true Level: B2
哈利开了一整天车——他一定很累。
Harry's been driving all day - he ___must be tired.
那对她来说一定非常令人沮丧。
It ___must have been very upsetting for her.
没剩食物了——他们一定都吃光了。
There's no food left - they ___must have eaten it all.
