The house has been in bad repair since he lived in it.
　　The house has been in bad repair since he moved out.
　　I haven’t eaten snails since I was a student at Indiana University.
　　I haven’t eaten snails since I left Indiana University.
　　(4)如若since從句中的動(dòng)作或狀態(tài)延續(xù)到說(shuō)話時(shí)間，通常要用持續(xù)性動(dòng)詞或表狀態(tài)動(dòng)詞的現(xiàn)在完成時(shí)。
　　He has written to me frequenthy since I was ill.
　　自從病愈以來(lái)……
　　He  has written to me frequenthy since I have been ill.
　　自從我生病以來(lái)……
　　I haven’t seen you since I’ve been back.
　　I haven’t seen you since I was back.
　　(5)區(qū)別
　　The house has been in bad repair since he lived in it.
　　The house has been in bad repair since he has lived in it.
　　He has stayed here for 3 hours.
　　He stayed here (since) 3 hours ago.
　　He has stayed here since 3 O’clock.
　　(6)在表示“第……次做某事”時(shí)常使用現(xiàn)在完成時(shí)。
　　It’s the 1st good meal I’ve had for ages.
　　It’s the 3rd time this has happened.
　　It’ll be the 1st time I’ve spoken in public.
　　(7)如果It之后的be動(dòng)詞用的是was,則that分句中通常用過(guò)去完成時(shí)。
　　It was  the 1st time he hadn’t worked on Saturday.
　　It was the 1st time she’d been at a summer school and she thoroughly enjoyed it.