----- Nội dung ảnh ----- 4. Angelina Jolie began taking an interest in charity work. She was filming in Cambodia then. 5. While I was walking along the street, I noticed a homeless boy sleeping in the cardboard. 6. John began playing the piano 10 years ago. 7. They last visited me five years ago. 8. May I borrow your bicycle? 9. Would you mind the pollution problems? 10. The students have discussed the pollution problems since last week.