past of can can 的过去式 ■used to indicate possibility 可能 they could be right. 他们可能是对的。 I would go if I could afford it. 如果负担得起我会去的。 ■used in making polite requests (用于礼貌的请求)可以;能够 could I use the phone?. 我可以用这个电话吗?。 ■used in making suggestions (用于提建议)可以 you could always ring him up. 你可以随时给他打电话。 ■used to indicate annoyance because of something that has not been done (对未做的事情表示恼怒)本可以;本来应该 they could have told me!. 他们本该告诉我的!。 ■used to indicate a strong inclination to do something (表示做某事的强烈愿望)想要 he irritates me so much that I could scream. 他让我如此恼怒,以至于我都想尖叫了。
用法
For a discussion on the use of could of instead of could have, see usage at have