\31. I've been looking for this book…………….a long time. 32. I've been working…………….I got up. 33. The kettle has been boiling…………….ten minutes 34. They have been living in Madrid ……………..1972. 35. He has been in prison……………… four years. 36. He has known about the fact …………….a long time. 37. Conditions have changed a lot ……………….we were children. 38. Our teacher has been very ill …………….the last month. 39. I haven't eaten anything …………….twenty-four hours. 40. In fact he is always very rude. We have been waiting for him …………..half an hour. 41. I haven't seen him for three years. It is because I haven't been there…………..I left school. 42. I have been trying to mend this old fashioned car……………… hours. 43. One of my friends has been teaching in Tokyo…………….. three years. I haven't met him since last year. 44. I haven't enjoyed myself…………….two weeks since I heard that my final exam grades were low. 45. I know that you have never seen a lion………. you were born. Then now I say that we can go to the zoo and see one.

Phương pháp làm:
- Đối với câu số 31: Sử dụng thì hiện tại hoàn thành (present perfect) cấu trúc "have/has + been + V-ing" để diễn tả hành động đã bắt đầu trong quá khứ và vẫn tiếp tục đến hiện tại.
- Đối với các câu từ 32 đến 45: Sử dụng thì hiện tại hoàn thành (present perfect) cấu trúc "have/has + V3/P.P" với từ "since" để nêu thời gian bắt đầu của hành động và thời điểm hiện tại.

Câu trả lời:
31. I've been looking for this book for a long time.
32. I've been working since I got up.
33. The kettle has been boiling for ten minutes.
34. They have been living in Madrid since 1972.
35. He has been in prison for four years.
36. He has known about the fact for a long time.
37. Conditions have changed a lot since we were children.
38. Our teacher has been very ill for the last month.
39. I haven't eaten anything for twenty-four hours.
40. In fact he is always very rude. We have been waiting for him for half an hour.
41. I haven't seen him for three years. It is because I haven't been there since I left school.
42. I have been trying to mend this old fashioned car for hours.
43. One of my friends has been teaching in Tokyo for three years. I haven't met him since last year.
44. I haven't enjoyed myself for two weeks since I heard that my final exam grades were low.
45. I know that you have never seen a lion since you were born. Then now I say that we can go to the zoo and see one.

The kettle has been boiling for ten minutes, so the water should be hot enough to make tea.

I've been working since I got up because I have a lot of tasks to complete and a deadline to meet.

I've been looking for this book for a long time because it is a rare and sought-after book in the market.