根据汉语提示完成句子。
1.______________(他关上电视机)when the programmne was over.
2._______________(我已见过他几次)since he left school.
3.I'll go to the post office___________(如果明天不下雨).
4. You won't be able to pass the exam__________(如果你不努力学习).
1.He turned off the TV set
2.I have seen him several times
3.if it doesn't rain tomorrow
4.if you don't work hard