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 telescope
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"

=>

V/
1. Many natural disasters have been caused by global warming.
2. After they had provided food, they cleared up the debris.
3. Quynh will be 28 next week.
4. If I didn't have to help my dad with something, I could come.
5. We had just got on the plane, the pilot told us to get off again.
6. Peter asked his colleague not to open the laboratory that day.
7. Phong asked Dr.Nelson if the Earth would ever be visted by aliens.
8. Tom asked the presenter how and when the universe had been created.
9. I asked John if he had ever looked through a telescope.
10. She asked Mr.Armstrong "How long have you worked on space projects?"