could的用法

could
could
AHD:[k‹d]
D.J.[kud]
K.K.[k&d]
v.aux.（助动词）
can的过去式
Used to indicate ability,possibility,or permission in the past:
用来表示过去的能力、可能性或允许：
I could run faster then.It could be no better at that time.Only men could go to the club in those days.
那时我能跑得更快.那时好得不能再好了.在当时,只有男人可以去俱乐部
Used with hypothetical or conditional force:
用来表推测或条件：
If we could help,we would.
如果我们能帮上忙,我们会帮的
Used to indicate tentativeness or politeness:
用于表示试探性或礼貌：
I could be wrong.Could you come over here?
我也许错了.你能到这边来吗?