Bài 3. Tính nhanh: a) A= 1.2 + 2.3+ 3.4 +…+ 100.101 b) B= 1.2.3 + 2.3.4 + 3.4.5 +…+ 100.101.102 Bài 4. Tính giá trị các biểu thức sau bằng cách hợp lý: a) A = 714 + 382 + 286 + 318 b) B = 35.34 +35.86 +65.75 +65.45 c) C = (257.139 – 257 .39) : 100 d) D = 102 – 96 + 90 - 84 +…+ 54 – 48 e) E = 3 + 5 + 7 + … + 2021 Bài 5. Tính nhanh: a) A= 1.2 + 2.3+ 3.4 +…+ 2020.2021 b) B= 1.2 + 2.3 + 3.4 +…+ n.(n + 1)

(căn bậc hai(2) + căn bậc hai(72) - căn bậc hai(18)) * căn bậc hai(2)

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we should do our homework before go to bed. it's a good

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Make the conditional clauses according to the facts provided: 1. He wasn’t able to answer the questions, so he failed the exam. ® If….......…………………………………………............................................... 2. I didn’t see you there, or I’d have said Hello. ® If….......……………………………………………………………… 3. The reason I haven’t been to Hawaii is that I can’t afford it. ® If….......………………………………………………..................................... 4. They won the games because two of our players were injured. ® If….......……………………………………………....................................................... 5. They are having a row because she borrowed his tennis racket and lost it. ® If….......……………………………… 6. I’m afraid of traveling by air, so I had to go to American by boat. ® If….......………………………………………........................................................... 7. She hasn’t studied English before. That’s why she’s in introductory class. ® If….......…………………………………………………………………………………………….. 8. One of the reasons I didn’t phone you was that I was very busy. ® If….......…………………………………………………………………………………………….. 9. Keep silent or you’ll wake the baby up. ® If…………………………………………… 10. Go right now or you’ll be late for the rain. ® If………………………… 11. As she is often absent from the class, she can’t keep pace with her classmates. ® Unless………………… 12. He had a flu because he ran out in the rain last night. ® If….......…….……………………………………………… 13. Be calm or you’ll make a wrong decision. ® If…........……………………………………………………………… 14. Without a visa, she couldn’t have come to this country. ® If….......………………………………………………………… 15. In the snowy weather we don’t go to school. ® If….......………………………………………………………………… 16. If the news turns out to be true, I’ll sell my shares at once. ® Should.……….………………………………………........................................... 17. If he fails the final examination, he won’t be able to graduate. ® Unless...…………………………………………............................................. 18. Provided that you leave an address we’ll be able to contact you. ® Unless...………………………………….………............................................................ 19. Without Jack’s help, I wouldn’t have been able to move the table. ® If….......………………………………………......................................................... 20. If you hadn’t told me about Sue’s hair, I wouldn’t have noticed. ® Unless...…………………………………………..................................................................... 21. The policeman showed me the way, so I found the house. ® If….......…………………………………………………................................................. 22. We stayed up all night, that’s why we’re so tired this morning. ® If….......…………………………………………...........................................................

Put the verbs in the brackets in the correct tense. 1. If he (win)__________________, he (get) _______________________$1000; if he (come) _____________________in second, he (get) _________________________ $500. 2. If you (feel) ___________________ too hot during the night, turn down the central heating. 3. Jack is a translator; he translates 1000 words a day and gets $100 a week, which he says isn't enough to live on. - Well, if he (want) ____________more money he (have) _________________to do more work. Advise him to translate 2000 words a day. 4. If you (finish) ___________________with your dictionary, I'd like to borrow it. 5. Jack (in canoe): Watch me! I'm going to stand up! Tom (on the bank): He's an idiot! If he (stand) ________________---up in the canoe it _____________________(capsize) 6. The lift wasn't working when I was here last. If it still (not work) _________________we (have)______________________ to use the stairs. 7. If you'd like some ice I (get) _________________some from the fridge. 8. He's only sixteen but he wants to leave school at the end of the term. - If he (leave) _______________ now he (be) ________________________sorry afterwards. 9. I expect it will freeze tonight. - If it (freeze) _________________tonight the roads (be) ______________________very slippery tomorrow. 10. That book is overdue. If you (not take) __________________it back to the library tomorrow you (have) __________________________to pay a fine. 11. You'd better take the day off if you (not feel) ______________________well tomorrow. 12. If you (like) _________________, I (get) __________________you a job in this company. 13. You can use my phone if yours (not work) ________________. 14. If you (not work) _____________________the meaning of a word you may use a dictionary. 15. If he was in, he (answer ) _______________________the phone. 16. You ( not be ) _____________________ any use to me unless you learn to type.

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Choose the best answer in each sentence below by circling it. 26. If the earth …… move around the sun, everything …… floated. A. didn’t / would be B. doesn’t / would be C. didn’t / will be D. don’t / would be 27. If he had taken my advice, he …… a rich man now. A. would be B. would have been C. had been D. were 28. Unless you …… smoking, you …… better. A. stop / won’t feel B. stop / will feel C. stopped / will feel D. stopped / would feel 29. If you are right, I ….. wrong. A. am B. will be C. would be D. would have been 30. If I …… to the party last night, I …… tired now. A. had gone / would be B. had gone / would have been C. went / would be D. went / would have been 31. Joe can’t hear ……. you shout. A. unless B. if C. providing D. whether 32. You can use my car …….you drive carefully. A. as long as B. whether C. until D. unless 33. You can smoke here …….you leave a window open to let the smoke out. A. as long as B. whether C. unless D. until 34. George won’t lend you any money …….you promise to pay him back. A. unless B. providing C. if D. as long as 35. I’m going now …… you want me to stay. A. unless B. providing C. provided D. as long as 36. If Jake …… to go on the trip, would you have gone? A. hadn’t agreed B. didn’t agree C. doesn’t agree D. wouldn’t agree 37. If I could speak Spanish, I …… next year studying in Mexico. A. would spend B. would have spent C. had spent D. will spend 38. Hung didn’t call Lan because it was too late. A. Hung will call Lan, if it is early. B. If it were not late, Hung would call Lan. C. Hung didn’t plan to call Lan, but he changed his mind at the last minute. D. If it hadn’t been so late, Hung would have called Lan. 39. We/ go/ zoo/ if/ it/ be/ nice/ Sunday. A- We go to the zoo if it is nice on Sunday. B- We will go to zoo if it is nice on Sunday. C- We will go to the zoo if it is nice on Sunday. D- We will go to the zoo if it is nice Sunday. 40. He said "If I had enough money, I could buy that dictionary." A- He said if he had enough money, he could buy that dictionary B- He said if he had had enough money, he could buy that dictionary. C- He said if he had enough money, he could have bought that dictionary. D- He said if he had had enough money, he could have bought that dictionary. 41. He didn’t hurried, so he missed the plane. A. If he had hurried, he might catch the plane B. If he hurried, he wouldn’t miss the plane C. If he had hurried, he could have caught the plane D. He didn’t miss the plane because his hurried.