大家好,小问来为大家解答以上问题。that must be hard on you，must be这个很多人还不知道,现在让我们一起来看看吧！

1、简单说一下吧.. must be doing:肯定某人正在做某事..He must be doing his homework.他一定在做他的作业 must have been doing:肯定某人一直在做的事..He must have been trying his best to study..他肯定一直都在尽力学习.. must表强烈的肯定。

2、shall不那么强烈。

3、could最弱..表推测的情况一般不用can。

以上就是【that must be hard on you，must be】相关内容。