Ex3. Chia các động từ trong ngoặc ra thì simple past hoặc present perfect: 1) We (studied)...............a very hard lesson the day before yesterday............................ 2) We (have studied)................................................almost every lesson in this book so far................. 3) We (have never watched)..........................that television program........................... 4) We (watched).....................an interesting program on television last night............... 5) My wife and I........................................(had travelled) by air many times in the past 6) My wife and I (travelled).................................. to Mexico by air last summer 7) I (have read)..................that novel by Hemingway sevaral times before. 8) I (read).........................that novel again during my last vacation. 9) I (had).........................a little trouble with my car last week. 10) However, I (have)......................... no trouble with my car since then. 11) I (have ) ………………..this toy since my birthday. 12) We (live )………………….in HN for ten years now and like it a lot. 13) The last time I (go) ……………………to HN was in May 14) When my parents were on holiday I ( stay)……………… with my aunt for a week 15) I (not see ) my son for ages .He (not visit ) ……………………..me since May 16) Tom ( be) …………….to HN twice .He loves it very much 17) My sister (work ) ……………………for an enterprise for two years .That was after college 18) I (move)……………… to HN in 2001 .I (be ) ………….there a long time now 19) It was so cold today that I (wear)…………… a sweater at school 20) So far this month there (be )……………………. three robberies in this street 21) When I was young I (meet )…………..him three times 22) In the past few years ,it (become )………….. more and more difficult to get into university 23) I (feel )………………better since I ( live) ……………….here 24) Since I (be ) ……………………in this city I ( not see)…………… him