Đáp án:
Giải thích các bước giải:
CMR:..............................................................
Cho hinh thoi ABCD goc A= 120.Tia Ax tao voi AB mot goc 15 va cat canh BC tai M, CD tai N. Chung minh: 1/AM^2 + 1/AN^2 = 4/3AB^2
Hỗn hợp X gồm axit panmitic, axit oleic và triglyxerit Y có tỉ lệ mol 5:1:2. Đốt cháy hoàn toàn m gam X cần 2,955 mol O2 thu được CO2 và H2O. Mặt khác thuỷ phân hoàn toàn m gam X băng NaOH vừa đủ thu được 34,66 gam hỗn hợp 2 muối. Khối lượng của Y trong m gam X là?
CMR:....................................................................
1+4+7+ 10 + 13 +16 + 19 +22+ 25 + 28+ 31+ 34
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Cho dạng đúng của động từ trong ngoặc Jame doesn't allow anybody (smoke) in his own car If each water (be) your happiness,i (give) you all the oceans in the world.
Mọi người giúpp mình bài 12 ý b với ạ .
I. Find the word which has a different sound in part underlined. Read the words out loud 1. A. other B. leather C. wealthy D. brother 2. A. television B. elephant C. section D. Swedish 3. A. allowed B. decided C. changed D. stayed 4. A. hotel B. postcard C. shore D. cold 5.A. Dutch B. Russian C. just D. use II. Choose the best answer 6. She asked me ............. I came from A. where B. if C. do D. whether 7. She said she ………. to the Moon when she had enough money. A. travel B. to travel C. would travel D. travelling 8. If we use water………., more people will have cleaner water. A. care B. carefully C. careless D. carelessly 9. The family took part ..................... a lot of activities in the festival. A. of B. on C. at D. in 10. If the teacher were here now, we’d ask him the difference ………. “science” and “technology”. A. among B. of C. between D. for 11. How about ............. to Thien Cam beach this weekend?. A. go B. going C. went D. gone 12. People who cannot hear or speak often communicate using ……….. A.pictures B.sounds C.codes D.signs 13. Teenagers spend most of their time playing computer game; ………., they lose their interests in daily activities. A.moreover B. so C.however D. as a result 14. Science is used in all corners of the world for the ………. of people. A.interest B.need C.profits D.benefit 15. All our English teachers are . . . . . speakers. A. native B. original C. foreign D. orginally III.Give the correct form of the verb in brackets 16.I (watch) …………… a science fiction film on TV at 9 .00 tonight. 17.Look at those clouds – I think it (rain)………………………….……….. 18- 19. If you use robots to do the housework, you (become)………………………….. lazy and you (not get)…………….. enough exercise. 20. We (walk )………………………along the street, we saw an accident. 21. If you (not break) ………… the rules, the teacher will not punish you. IV. Read the passage and choose the best answer The United States is a large country. It is the third largest in the whole world! It is located in a continent called North America. Parts of the United States touch three different oceans. The United States has tall mountains, wide plains, deserts, hills, rivers, lakes, volcanoes and even rainforests! People from all over the world have come to live in the United States. There are 50 states in the United States. The newest states, Alaska and Hawaii, are not connected to the other states. Alaska is the largest state and Hawaii is a chain of islands in the Pacific Ocean. 22.The United States is the _________ country in the world. A. second largest B.largest C.smallest D.third largest 23.Alaska is ___________ and Hawaii is __________. A. a chain of islands/ the largest state B. the largest state/ a chain of islands C.a chain of islands/ the largest state D.not connected to the other states/ the largest state 24.The United States does not have ____________. A.50 states B. volcanoes C. mountains D.continents 25.Parts of the United States touch _________ different oceans. A.1 B.2 C.4 D.3 26.What continent is the United States in? A.North America B.Australia C. Africa D.Europe V. Read the passage and mark the letter A, B, C or D to indicate the correct word or phrase that best fits each of numbered blanks It is estimated that about 200 million people who use the Internet computer network around the world. The Internet allows people _____ (27) at home instead of traveling to work. The Internet allows businesses to communicate with customers and workers in any part of ____ (28) world for the cost of a local telephone call. E.mail allows____ (29) to send documents, pictures and other data from one part of the world to another in at least 5 minutes. People can use the Internet to do shopping. ____ (30) saves a lot of time. It is possible to use the Internet for _____ (31) – students may connect with their teachers from home to send or receive e.mail or talk their problems through “on-line” rather than attend a class. 27. A. work B. to work C. worked D. works 28. A. a B. an C. the D. one 29. A. use B. users C. useful D. useless 30. A. This B. These C. Those D. They 31. A. educate B. educator C. educating D. education giúp mk vs mk đang cần gấp
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