30. He isn’t going to buy that house. ………………………………………………………………… 31. This terrorist has kept 3 hostages for a week. …………………………………………………… 32. He hasn’t seen you for years. …………………………………………………………………… 33. The examiner will read the passage 3 times. …………………………………………………… 34. An earthquake destroyed the town. …………………………………………………………… 35. He didn’t type the letter last night. ……………………………………………………………… 36. They will pick me up at my house. …………………………………………………………… 37. When did you see him in that bank? …………………………………………………………… 38. A man returned the keys to me. ………………………………………………………………… 39. Mary will see her friends off at the station. …………………………………………………… 40. They have to pull down that building. …………………………………………………………… 41. He gave me a knife to cut this bread. …………………………………………………………… 42. They used to drink beer in England ……………………………………………………………… 43. She can sew 3 shirts a day. ……………………………………………………………………… 44. Nobody has used this room for ages. …………………………………………………………… 45. I am translating an article into Vietnamese. …………………………………………………… 46. Someone is following me. ……………………………………………………………………… 47. The State will assign our students to different jobs. …………………………………………… 48. She read the letter again and again last night. ………………………………………………… 49. This is the first time they have written to us about this. …………………………………………………………………………………………………….

I. Change these sentences to the passive voice : 1. My students have met their friend at the station. ……………………………………………… 2. They didn’t allow Tom to take these books home. ……………………………………………… 3. The teacher won’t correct exercises tomorrow. ………………………………………………… 4. This well-known library attracts many people. ………………………………………………… 5. All students attended the meeting. ……………………………………………………………… 6. People say that he is intelligent. ………………………………………………………………… 7. He can’t repair my bike. ………………………………………………………………………… 8. Mary has operated Tom since 10 o’clock. ……………………………………………………… 9. Mr. Smith has taught us French for 2 years. …………………………………………………… 10. They didn’t look after the children properly. …………………………………………………… 11. Nobody swept this street last week. …………………………………………………………… 12. People drink a great deal of tea in England. …………………………………………………… 13. People speak English all over the world. ……………………………………………………… 14. Tom was writing 2 poems. ……………………………………………………………………… 15. She often takes her dog for a walk………………………………………………………………. 16. She didn’t introduce me to her mother. ………………………………………………………… 17. Farmers usually milk cows twice a day. ………………………………………………………… 18. Our teacher used to bid us talk in class. ………………………………………………………… 19. Workers were digging a large hole in the ground. ……………………………………………… 20. The car knocked a woman down in the street. ………………………………………………… 21. Cows were eating grass on the meadow. ………………………………………………………… 22. My cousin will meet you at the station. ………………………………………………………… 23. She is running her own company. ……………………………………………………………… 24. Visitors must leave umbrellas in the cloakroom. ……………………………………………… 25. My mother used to make us clean the house. ……………………………………………………. 26. John hasn’t finished his homework. ……………………………………………………………... 27. I will shut the door if you like. ………………………………………………………………… 28. We have just seen a horrible accident. ………………………………………………………… 29. At 7 p.m., Mrs. Smith was making cakes. ………………………………………………………

Cần bao nhiêu gam đồng để khử hoàn toàn lượn ion bạc có trong 85ml dung dịch AgNO3 0,15M?

II. Change the verbs in brackets into the correct form : WANGARI MAATHAI Wangari Maathai …………………… (award) the Noble Prize in 2004. She ………………… (praise) by the Noble committee as a source of inspiration for everyone in Africa fighting for sustainable development, democracy and peace. When she started the Green Belt movement in 1977, Kenya was suffering from deforestation and desertification. Thousands of tree ……………… (cut down) and many family ……………………… (leave) in poverty as a result. Since then, her most successful campaign to mobilize women to plant some 30 million trees ……………………… (copy) by others countries. During that time, the movement …………………… (transform) into a campaign on education, nutrition and other issues. Her campaign has not always been popular, Mrs. Maathai ……. …………… (arrest) several times for campaigning against deforestation in Africa, and once she ………………….. (beat) unconscious by the heavy handed people. But in elections in 2002, she ………………………. (elect) as an MP as part of an opposition coalition which swept to power, and she ………………… (appoint) as a deputy environment minister in 2003.

50. Someone had invented electric lights before I was born. ……………………………………………………………………………………………………. 51. Before they took exams they had revised their lessons. …………………………………………………………………………………………………… 52. When he came home his father was reading a newspaper. …………………………………………………………………………………………………… 53. My father will take me to Ho Chi Minh City next week. ………………………………………………………………………………………………….. 54. When I was 18 years old, my parents allowed me to go out in the evening. …………………………………………………………………………………………………… 55. You were wearing your new hat when I met you yesterday. …………………………………………………………………………………………………… 56. He is preparing everything for the presidential election. …………………………………………………………………………………………………… 57. Last Friday, when I came to Jane’s house, she had finished all exercises. …………………………………………………………………………………………………… 58. Countries are finding a way to solve the problem. …………………………………………………………………………………………………… 59. He put the letter in the drawer, and then he locked it up. …………………………………………………………………………………………………… 60. By the end of this year, we will have learnt 2,000 English words. …………………………………………………………………………………………………… 61. Her father was planting different kinds of flowers in the garden. …………………………………………………………………………………………………… 62. The Prime Minister is making a speech at the moment. …………………………………………………………………………………………………… 63. The doctor pulled out one of my teeth yesterday morning. …………………………………………………………………………………………………… 64. His wife usually brings him sandwiches at lunch time. …………………………………………………………………………………………………… 65. The light went out while I was making a cup of tea. …………………………………………………………………………………………………… 66. When she went to Barcelona, she learnt some Spanish. …………………………………………………………………………………………………… 67. The students of chemistry made many experiments last week. …………………………………………………………………………………………………… 68. For the past years, I have done all my washing by hand. ……………………………………………………………………………………………………

MN ƠI AI GIÚP MIK VỚI Ạ Hai pha dao động điều hòa cùng phương cùng tần số, dao động thứ nhất có biên độ A1=6cm, pha ban đầu pi/6 và dao động thứ hai có biên độ A2 pha ban đầu 5pi/6. Biên độ A2 thay đổi được. Biên độ dao động tổng hợp A có giá trị nhỏ nhất là bao nhiêu

Chứng minh rằng 1/ (sin x + cos x)^2 = 1+2sin x . cos x 2/ sin^4x + cos^4x = 1-2sin^2x . cos^2x 3/ sin^6x + cos^6x = 1-3sin^2x . cos^2x 4/ 1-sinx / cos x = cos x / 1+sin x giúp mình với nhaaaa

complex sentences from cach pair of sentences. Use the subordinator prov and make any necessary changes. 1. It might rain. Take an umbrella with you. (in case) 8. They were reading. Their mother was watching TV. (while) 9. He had checked every door. He went out today. (before)

Passive voice with two objects 1. Rachel will give you some advice. You ..................................................................................................................................................... Some advice ....................................................................................................................................... 2. I sent him a letter. ............................................................................................................................................................ ............................................................................................................................................................ 3. The police officer showed us the way. ............................................................................................................................................................ ............................................................................................................................................................ 4. Our neighbor gave me a lift. ............................................................................................................................................................ ............................................................................................................................................................ 5. She told me a lie. ............................................................................................................................................................ ............................................................................................................................................................ 6. They have written her a postcard. ............................................................................................................................................................ ............................................................................................................................................................ 7. Kerrie will make you a cup of tea. ............................................................................................................................................................ ............................................................................................................................................................ 8. The waiter has not brought us the coffee. ............................................................................................................................................................ ............................................................................................................................................................ 9. They did not offer her a seat. ............................................................................................................................................................ ............................................................................................................................................................ 10. We bought Betty a bit of butter. ............................................................................................................................................................ ............................................................................................................................................................

Mọi người giúp em câu này với ạ ! 2sin$^{3}$ ( x + $\frac{\pi}{2}$ ) + cos2x + cos ( $\frac{9\pi}{2}$ - x ) = 0