Hoàn thành phản ứng theo sơ đồ: butan---> metan--> axetilen-->vinyl clorua-->PVC.

VI. Choose the best answer (A, B, C or D) that is the same meaning with the italic sentence. Question 31. Alexander Graham Bell invented the telephone in 1876. A. The telephone is invented by Alexander Graham Bell in 1876. B. The telephone was invented by Alexander Graham Bell in 1876. C. The telephone in 1876 were invented by Alexander Graham Bell. D. The telephone will be invented by Alexander Graham Bell in 1876. Question 32. We are interested in protecting environment. Our teacher is pleased. A. Our teacher is pleased that we are interested in protecting environment. B. We are interested in protecting environment that our teacher is pleased. C. Our teacher is pleased to protect environment. D. Our teacher is pleased to be interested in protecting environment. Question 33. My father bought this house 2 years ago. A. This house was bought by my father 2 years ago. B. This house bought by my father 2 years ago. C. This house were bought 2 years ago. D. This house 2 years ago is bought by my father. Question 34. The car is very beautiful. It is made in Japan. A. The car is very beautiful made in Japan. B. The car made in Japan is very beautiful. C. The car making in Japan is very beautiful. D. The car is made beautiful in Japan. Question 35. Viet Nam is a country which exports a lot of rice. A. Viet Nam is a rice –exporting country. B. Viet Nan is an exporting –rice country. C. Viet Nam is a rice –exported country. D. Viet Nam is a country exporting - rice. Question 36. It’s two years since I last visited China. A. I haven’t visited China since two years. B. I haven’t visited China for two years. C. I have visited China since two years. D. I have visited China for two years. Question 37. He started living in Paris in 1990. A. He has started living in Paris since 1990. B. He has lived in Paris for 1990. C. He has been living in Paris for 1990. D. He has lived in Paris since 1990. Question 38. He isn’t strong enough to lift that box. A. He is too weak to lift that box. B. He is weak enough to lift that box. C. He is enough strong to lift that box. D. He isn’t too weak to lift that box. Question 39. I have never been to London before. A. This is the first time I have been to London. B. This if the first time I had been to London. C. It is the first time I have been to London. D. Both A and C are correct. Question 40. Although he is poor, he lives a happy life. A. Despite his poor, he lives a hppay life. B. Despite of his poverty, he lives a happy life. C. Despite being poor, he lives a happy live. D. Both A and C are correct.

Một gia đình cần làm 1 ngôi nhà, họ cần thêm 740 kg vôi tôi nữa để hoàn thiện. Hỏi: a. Họ cần phải mua bao nhiêu kg vôi sống ? b. Họ phải có bao nhiêu lít nước để tôi vừa đủ lượng vôi sống trên ? ( Biết khối lượng riêng của nước là 1kg/l ) Hướng dẫn: áp dụng phương pháp giải BT tính theo PTHH, nên tính theo tỷ lệ về khối lượng: PTHH: CaO + H2O Ca(OH)2 Tỷ lệ klg: 56g 18g 74g x kg y kg 740 kg Giúp mình nhanh nhé Cảm ơn

giúp mk bài 9 ý e ,f , g ,h vs ạ

V. Read the passage and answer the questions. Technology has advanced to the point where instant communication anywhere in the world is an everyday fact of life. Technology has improved, and has a positive impact on communication as a whole in many (26) __________ . It has increased the reliability of sending messages to others, made it easier to meet new people and keep (27) __________ touch with friends. Modern communication is handled by wireless signals, undersea cables, satellites and other (28) __________ technology, ensuring the fast delivery of messages and data to any locations. The accessibility of technology also means that you don’t need to be in any special locations like a post office or mail room to send a message; all you need is a cell phone. Online communication has (29) __________ the door to new ways of communicating with strangers and taking part in communities. Chat rooms, (30) __________ forums and dating sites let people meet each other and get to know more people without having to be there in person. Question 26. A. methods B. means C. forms D. ways Question 27. A. on B. out C. for D. in Question 28. A. important B. high C. simple D. basic Question 29. A. opened B. closed C. been opened D. been closed Question 30. A. channel B. discussion C. cyber D. media

Câu 6: Cho biết nhiệt độ nóng chảy của chì là 327oC . Phát biểu nào sau đây sai? 1 điểm A: Khi chì tồn tại cùng lúc ở cả thể rắn và lỏng, chì có nhiệt độ là 327oC. B: Khi chì đang nóng chảy nhiệt độ của chì là 327oC. C: Chì sẽ đông đặc ở nhiệt độ thấp hơn 327oC. D: Ở nhiệt độ 100oC, chì tồn tại ở thể rắn. Câu 7: Trường hợp nào dưới đây không xảy ra sự nóng chảy? 1 điểm A: Đúc trống đồng. B: Thắp nến. C: Thả một viên nước đá vào li nước. D: Đổ một muỗng muối vào li nước. giúp mình với nhé mình hết điểm rồi

William Will not repair the car

Tìm các giá trị của m để biểu thức sau luôn dương: x^2-4x+m-5 Giải giúp mik vs mik cần gấp ạ!

Dựa vào thực tế lịch sử dân tộc ta, chứng minh tính đúng đắn của nhận định sau: Đoàn kết, đoàn kết, đại đoàn kết – Thành công, thành công, đại thành công ( Hồ Chí Minh). a Tìm các luận điểm chính cần có trong bài văn.

I. Choose the word which has the underlined part pronounced differently from the rest. Question 1. A. recycle B. medical C. chemical D. athletic Question 2. A. pollute B. botanic C. contaminate D. economy Question 3. A. into B. history C. tiny D. disease II. Choose the word which is stressed differently from the rest. Question 4. A. national B. grammatical C. medical D. chemical Question 5. A. athletic B. historic C. dramatic D. classic Question 6. A. scientifically B. economic C. artistic D. scientific III. Choose the correct answer to complete each sentence. Question 7. Water pollution can put negative __________ on our health. A. contamination B. affects C. effects D. problems Question 8. A: How can light pollution __________ animals? B: It can make animals change their behavior patterns. A. cause B. make C. affect D. lead Question 9. The dove is a universal __________ of peace. A. symbolizing B. symbolize C. symbolic D. symbol Question 10. The city has an atmosphere which is quite _______. You will never feel like that in other places. A. important B. normal C. unique D. common Question 11. __________ about the storm that stroke Hanoi last night? A. Did you hear B. Do you heard C. Have you hear D. Did you heard Question 12. Many people __________ because of the earthquake last week. A. did injure B. injured C. have injured D. were injured Question 13. When I looked at the river, I knew it __________ for a long time. A. had contaminated B. had been contaminated C. was contaminated D. contaminated Question 14. All flights to Ha Noi had to be cancelled __________ the storm. A. as a result B. due to C. because D. so Question 15. When we were young, we __________ in the river near our home. A. used to swim B. have swum C. had swum D. were swimming Question 16. Our coffee is a very products in the international market due to the high quality and the reasonable price. A. competition B. compete C. competitor D. competitive Question 17. We both admired his in helping other people. (generous) A. generous B. generously C. generosity D. more generous Question 18. The dress was , so I did not have a look on it. (attract) A. attraction B. unattractive C. attractive D. attracted Question 19. He _______ with most of the people in last night's face-to-face meeting. He was so talkative. A. Communicated B. communicating C. communicative D. communication Question 20. They were very surprised when they knew his . A. nation B. national C. nationally D. nationality