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4. Angelina Jolie began taking an interest in charity work. She was filming in Cambodia then.
(WHILE)
->Angelina Jolie was.
5. While I was walking along the street, I noticed a homeless boy sleeping in the cardboard
(WHEN)
->I was ....
6. John began playing the piano 10 years ago.
-> John has ....
7. They last visited me five years ago
-> They haven't ...
8. May I borrow your bicycle?
mind.......
->Would you mind .....
....?
9.The students have discussed the pollution problems since last week.
->The pollution problems ....