he will have to stay in hospital. that's what he must do .这是正确的句子,我想问,如果是that's what he must be doing ,就怎么错了
问题描述：
he will have to stay in hospital. that's what he must do .这是正确的句子,我想问,如果是
that's what he must be doing ,就怎么错了
答
he will have to stay in hospital .that's what he_ 1.has done 2.when will they___let him go ___? 1.let him go 2.let him to
答
will have to do表示将不得不做，但最终还未做，所以回答的时态也要和前句一致，
A为现完，已做过， B必须做，还未做， C一定正在做， D肯定已经做过
答
因为前面描述的行为,也就是stay in hospital还没有发生,所以不可以是正在进行时态.
答
he must be doing 你看着不觉得很奇怪么