----- Nội dung dịch tự động từ ảnh ----- 8. She has written this letter for 30 minutes. =>The letter .. 9. The workers håve taken several steps to whiten the palm leaves. -> Several steps 10. The students have discussed the pollution problems since last week. -> The pollution problems .. 11. Somebody has described Keith Jones as the world's greatest guitarist. -> Keith Jones ... 12. The committee appointed Alice secretary for the meeting. -> Alice secretary ..