EX6:
1.This is the first time I've ever painted a mural over graffiti.
I have never painted a mural over graffiti before.
2.Mr. Binh started recycling rubbish two years ago.
Mr. Binh has recycled rubbish for two years / been recycling rubbish for two years.
3.David failed the exam because of his laziness.
Because David was lazy, he failed the exam.
4.They haven't cleaned up the street for five months.
It's been five months since they last cleaned up the street.
5.We have donated books and clothes for ten years.
We began donating books and clothes ten years ago / to donate books and clothes ten years ago.