1. Global warming has caused many natural disasters.
--->Many natural disasters have been caused by global warming
2. They provide food then cleared up the debris.
--->After they had provided food, they cleared up the debris
3. It's Quynh's 28th birthday next week.
--->Quynh will be twenty eight next week
4. I can't come because I have to help my dad with something.
--->If I didn't have to help my dad with something, I could come
5. As soon as we got on the plane, the pilot told us to get off again.
--->We had just got on the plane, the pilot told us to get off again
6. "We don't open the laboratory today."Peter said to his colleague
--->Peter asked his colleague not to open the laboratory that day
7. "Will the Earth ever be visited by aliens?" Phong said to Dr.Nelson.
--->Phong asked Dr.Nelson if the Earth would ever be visited by aliens
8. "How and when was the universe created?" Tom asked the presenter.
--->Tom asked the presenter How and when the universe had been created
9. "Have you ever looked through a telescope?" I asked John.
--->I asked John if he had ever looked through a telescopev
10. She asked Mr. Armstrong how long he had worked on space projects.
--->She asked Mr. Armstrong:" How long have you worked on space projects"

9. "Have you ever looked through a telescope?" I asked John.
--->I asked.John if he had ever looked through a telescope......
10. She asked Mr. Armstrong how long he had worked on space projects.
--->She asked...Mr.Armstrong: "How long did he work on space projects?".....
11. Scientist have invented new devices to help people live a longer life.
--->New devices...have been invented to help people live a longer life by scientists.....
12. The man had a broken leg. He tried to save his wife.
--->In spite of...having a broken leg, the man tried to save his wife........
13. I can't tell you because I don't know the answer.
--->If...I knew the answer, I could tell you......
14. They will do the test well. They will review them all hard
--->If....they review them all hard, they will do the test well.....
15. The rescue workers evacuated the villagers in the raged flood to the safe place last night.
--->The villagers in the raged flood.were evacuated to the safe place by the rescue workers last night.........
16. The students will provide aids for the homeless people tomorrow.
--->Aids.will be provided .for the homeless people tomorrow by the students.....

1. Global warming has caused many natural disasters.
--->Many natural disasters have been caused by global warming.
2. They provide food then cleared up the debris.
--->After they had provided food, ther cleared up the debris.
3. It's Quynh's 28th birthday next week.
--->Quynh will be 28 next week.
4. I can't come because I have to help my dad with something.
--->If I didn't have help my dad with something, I could come .
5. As soon as we got on the plane, the pilot told us to get off again.
--->We had just got on the plane, the pilot told us to get off again.
6. "We don't open the laboratory today."Peter said to his colleague
--->Peter asked his colleague not to open the laboratory that day.
7. "Will the Earth ever be visited by aliens?" Phong said to Dr.Nelson.
--->Phong asked Dr.Nelson if the earth would ever be visited by aliens.
8. "How and when was the universe created?" Tom asked the presenter.
--->Tom asked the presenter how and when ther universe had been created.
9. "Have you ever looked through a telescope?" I asked John.
--->I asked.John if he had ever looked through a telescope
10. She asked Mr. Armstrong how long he had worked on space projects.
--->She asked Mr.Armstrong: "How long did he work on space projects?"
11. Scientist have invented new devices to help people live a longer life.
--->New devices have been invented to help people live a longer life by scientists
12. The man had a broken leg. He tried to save his wife.
--->In spite of having a broken leg, the man tried to save his wife.
13. I can't tell you because I don't know the answer.
--->If I knew the answer, I could tell you.
14. They will do the test well. They will review them all hard
--->If they review them all hard, they will do the test well.
15. The rescue workers evacuated the villagers in the raged flood to the safe place last night.
--->The villagers in the raged flood.were evacuated to the safe place by the rescue workers last night.
16. The students will provide aids for the homeless people tomorrow.
--->Aids will be provided for the homeless people tomorrow by the students.