I'm afraid it might rain tonight.
Could I borrow your thermos
It's a nice day today. We could go for a walk.
E.情态动词是互相排斥的,一般不允许两个意义相近的情态动词连用。
【误】Soldiers must have to obey orders.
【正】Soldiers have to obey orders.
【正】Soldiers must obey orders.
【误】Can I be able to borrow two books at a time
【正】Can I borrow two books at a time
【正】Will I be able to borrow two books at a time