đề bài : Fill the spaces in the following sentences by using for or since

Here are the answers to the given sentences using "for" or "since": 22. I've been awake since four o'clock. 23. I've been awake for a long time. 24. We've had no gas since the strike began. 25. I've earned my own living since I left school. 26. Nobody has seen him since last week. 27. The police have been looking for me for four days. 28. I haven't worn low-heeled shoes since I was at school. 29. He had a bad fall last week and hasn't left the house since then. 30. He has been under water for half an hour. 31. That tree has been there for 2,000 years. 32. He has been Minister of Education since 1983. 33. I've been trying to open this door for forty-five minutes. 34. He hasn't eaten anything for twenty-four hours. 35. We've had terrible weather for the last month. 36. Nobody has come to see us since we bought these bloodhounds.