Ex1 : 1. have worked ( đây là thì HTHT vì có dấu hiệu là since ) 2. have just bought ( thì HTHT vì có just ) 3. haven't planned ( thì HTHT vì có yet ) 4. has written ( thì HTHT vì có for) 5. hasn't seen ( thì HTHT vì có for ) 6. hasn't started ( thì HTHT vì có yet ) 7. Has he already spoken 8. Hasn't spoken ( thì HTHT vì có yet ) Ex2 : 1. has just gone 2. have lived ( thì HTHT vì có since ) 3. have collected 4. has already read 5. have seen 6. have you washed 7. have seen ( this is the first time là dấu hiệu của thì HTHT ) Ex3 : 1. lives ( thì HTD , he là số ít nên thêm s) 2. are living ( thì HTTD vì có at present ) 3. is having ( thì HTTD ví có now ở vế trc ) 4. like / don't go ( thì HTD vì có often ) 5. doesn't jog 6. has ( thì HTD vì có everyday) 7. is shining ( thì HTTD vì có look!) 8. rises ( thì HTD vì có always ) 9. drinks ( thì HTD vì có usually ) 10. is wanting ( thì HTTD vì có now ) 11. are you doing / am watching 12. am litening ( thì HTTD vì có wait a moment ) 13. always come 14. do Susan do / watches / listens 15. is shouting ( thì HTTD vì có listen! ) 16. takes ( thì HTD vì có regularly : thường xuyên ) 17. boils 18. boils 19. have stayed 20. celebrate