can的过去式英文

　　This could cause serious damage to the country's economy.

　　这可能对国家的经济造成严重破坏。

　　The database could be used as a teaching resource in colleges.

　　数据库可以用作大学里的一种教学辅助手段。

　　I think we could all use a drink after that!

　　我想我们在事情办完之后都得痛快地喝一杯。

　　He could just make out three people through the mist.

　　透过薄雾他勉强能看出有三个人。

　　The operation could prolong his life by two or three years.

　　这次手术可使他多活两三年。