có giải thích nhé các bạn. Exercise 4: Chia dạng đúng của động từ trong ngoặc 11. Since I left Venezuela six years ago, I (return) to visit friends and family several times. 12. When my parents (arrive) for a visit tomorrow, they will see our baby for the first time. 13. Don't worry. I (finish) the report by 10 o'clock. 14. I'll return Bob's pen to him next time I (see) him. 15. "I [go] out to buy a morning newspaper." "But it (rain) now. Why don't you wait until the rain (stop)?" 16. Whenever I travel abroad, I (forget) something I need. 17. Hurry up or you (be) late for class. 18. He (be) to the theater three times this month. 19. Hurry up or the film (be) over before we (get) home. 20.Before I (start) the car, all passengers had buckled their seat belts.