1、can 表示现在的能力,could 表示过去的能力。
例句:
He can speak a little English now.
She could play the piano when she was five.
2、在表示请求许可时,没有时间区别,在语气上could 更加委婉客气。
例句:
Can I use your pen ?
Could I have a look at your book ?
3、在表示可能性方面,没有时间区别,can 可能性比could 大;表示逻辑上或理论上的可能性,而不是某种实际上将要发生或正在发生的可能性。
1、I could hardly refuse, could I?
2、She could scarcely complain, could she?
3、Tempers could fray.
4、This could be catastrophic.
5、We could talk Italian.
6、Can you please pass me the book?你可以把书递给我吗?
7、Can you help me?你能帮我一下吗?
8、Can you swim?你游泳吗?
9、Can you speak English?你会说英语吗?