can的过去式是couldI could lend you some money.I couldn't lend you some money.Could you lend me some money?Yes,I could.No,I coudn't.过去式的用法和原形是一样的.变否定直接加not,变疑问直接提前.【希望解决...什么结构，不都给你写完了吗？could+动词原形，按照例句看。