Ex2.Choose the suitable options to complete the following sentences. (Lựa chọn những phương án phù hợp để hoàn thành các câu sau.) 6. We have finished/finished our homework already. Can we go outside now? 7. When he has been/was 10 years old, he went to school in New York. 8. Suzy hasn't read/read the third book in the series yet. 9. Have you ever met/Did you ever meet the new mentor before? 10. What have you done/did you do so far with that non-profit organization? 11. Did they offer coupons for free pizza in Royal City last week? - Yes, they have./Yes, they did. Ex3.Decide whether the following sentences are Correct or Incorrect in terms of grammar.(Hãy xác định những câu dưới đây là Đúng hay Sai về mặt ngữ pháp.) 12. Have you ever worked as a volunteer? 13. I have cleaned up my room last week. 14. I have stayed in San Francisco for two years. 15. Did she never used public transport? 16. Last month, we started a community garden project. 17. Yesterday, I've gone to the nursing home to visit my grandfather. 18. She hasn't finished her work yet. 19. Hey Tom! Did you cook a meal at a shelter for homeless people last week? 20. They raised 20 million dong for the fund so far.