Could I borrow that book when you've finished reading it?that book 是一起的,就是“那本書”的意思整句話意思是：當(dāng)你已經(jīng)讀完那本書的時(shí)候我能借一下么?you've finished reading it 就是明顯的一個(gè)現(xiàn)在完成時(shí)啊...you've finished reading 現(xiàn)在完成進(jìn)行時(shí)嗎？那reading是動(dòng)名詞?呵呵。不是的 have done sth這里的have已經(jīng)跟了finished了呀。然后finish+doing的結(jié)構(gòu)所以變成了have finished doing sth 啊再舉個(gè)例子 I have decided to go to USA.這里have decided 已經(jīng)符合have done 的語(yǔ)法了、然后decide+to do sth綜合就變成了have decided to do sth 了、還有什么詞+doing的結(jié)構(gòu)？好多的。一時(shí)也說(shuō)不過(guò)來(lái)你初中的吧？多看書。很多句型書里課文里很明顯可以找到！有些詞doing 也可以 to do 也可以 但用法不同