2CH4-1500C-làm lạnh nhanh->C2H2+3H2
C2H2+H2-PbCO3->C2H4
nCH2=CH2-xt,to->(CH2-CH2)n
3C2H2-xt,to->C6H6
3.A. clothes B. fireworks C. scissors D. mountains 4.A. stadium B. place C. paddy D. lake 5.A. lunch B. music C. unpopular D. study II. Complete the sentences below using the correct form of comparative or superlative adjectives. Ex: - Lan is Hoa. (tall) Lan is taller than Hoa. - Nam is student in his class. (young) Nam is the youngest student in his class. 1. A new house is ……………………………… an old one. (expensive) 2. Motorbikes are ……………………………… bicycles. (fast) 3. My television is ……………………………… his television. (modern) 4. Summer is ……………………………… Spring. (hot) 5. Jane is ……………………………… her sister. (beautiful) 6. Skirts are ……………………………… dresses. (cheap) 7. Her English is ……………………………… my English. (good) 8. A bicycle is often ……………………………… a car in busy cities. (convenient) 9. Nile River is ……………………………… river in the world. (long) 10.This book is ……………………………… of these books. (interesting) 11. Ho Chi Minh City is ……………………………… city in Viet Nam. (big) 12.They are ……………………………… students in my class. (good) 13.These houses are ……………………………… in the village. (beautiful) 14.Winter is ……………………………… season in the year. (cold) 15.Airplane is ……………………………… means of transport. (fast) III. Give the correct form of the verbs in the simple future. 1. ……………………………… (they / come) tomorrow? 2. When ……………………………… (you / get) back? 3. If you lose your job, what……………………………… (you / do)? 4. They ……………………………… (do) it for you tomorrow. 5. My father ……………………………… (call) you in 5 minutes. 6. ……………………………… (she / get) the job, do you think? 7. We believe that she ……………………………… (recover) from her illness soon. 8. What ……………………………… (the weather / be) like tomorrow? 9. I promise I……………………………… (return) from school on time. 10. ( you / show )……………..me how to operate the new machine, please ? IV. Fill in the gap with should/ shouldn’t/ must/ mustn’t : 1.I don’t think you ………………………eat so much chocolate. It’s bad for your health. 2.I think waiters………………………………try to be pleasant with customers. 3.If you feel sick, you ……………………………… stay at home. It’s better for you. 4.I ……………………………… get my hair cut. I don’t like long hair. 5.We ………………………… go home. My mother has told me to arrive at ten o’clock. 6.I ……………………………… study hard. I want to pass the exam. 7.You ……………………………… accept things from strangers! 8.You ……………………………… steal things from shops. giúp mình với (hép miiiiiii)
Xác định công thức phân tử của các hợp chất sau: a. Hợp chất B có thành phần phần trăm của các nguyên tố là 39,32% Na ; 25,54%C ; 28,07 O và khối lượng mol của hợp chất là 142. b. Hợp chất A có khối lượng mol là 152 và phần trăm khối lượng của các nguyên tố là 36,84%Fe ; 21,05%S ; 42,11%O
Giúp mik câu 8 vs 5* và 1 cảm ơn nha
Làm cho minh 2 bài này với ạ mình sẽ vote 5 sao và đánh giá hay nhất cho ạ minh cảm ơn
NAME: …………………………………………………………………………………………………….… class 6A … Review 3 ( unit 7,8 ) Choose the word whose underlined part is pronounced differently from that of the others 1. A. though B. their C. thin D. them 2. A. flower B. poster C. local D. host 3. A. fair B. marry C. chair D. hair 4. A. reason B. feature C. idea D. teacher 5. A. bath B. healthy C. rather D. everything Odd one out 6. A. match B. stadium C. gym D. swimming pool 7. A. run B. play C. watch D. sport 8. A. better B. taller C. uglier D. smallest 9. A. game B. chess C. aerobics D. karate 10. A. broadcast B. producer C. report D. act Choose the best answer to fill in the blank. 11. I ________ Tom and Jerry many times. A. see B. am seeing C. have seen D. saw 12. ________ the film is late, I will wait to watch it. A. Although B. When C. But D. Because 13. Hoa ________ three goals for my team and he made it a hat trick. A. scored B. scores C. played D. got 14. ……………………. noise. Your brother is sleeping. A. Don’t make B. make C. making D. made 15. The mother told her son: “________swim in the lake. It's very dangerous." A. Do B. Don't C. can't D. Not swim 16. My sister likes going to the cinema ________ I like watching TV at home. A. or B. but C. and D. because 17. I first ________Ho Chi Minh City in 2013. A. been to B. visited C. go D. went 18. ……………………. do you play chess? – I never play chess A. How often B. When C. Why D. Who Choose the correct answers to complete the passage. Television is one of man’s most important (19)_____ of communication. It brings pictures and sounds from around the world into millions of homes. Through television, home viewers can see and learn (20)_____ people, places and things in faraway lands. TV even takes its viewers out of this world. It brings them coverage of America’s astronauts as the astronauts explore (21)_______ space. In addition to all these things, television brings its viewers a steady stream of programs that are (22)______ to entertain. In fact, TV provides many (23)_____ entertainment programs than any other kind. The programs include dramas, comedies, sports, and (24)______ pictures. 19. a. ways b. means c. ranges d. shows 20. a. at b. in c. for d. about 21. a. deep b. large c. outer d. open 22. a. happened b. designed c. composed d. guided 23. a. more b. even c. most d. hardly 24. a. lovely b. clear c. motion d. full
Treo vật m vào dưới lò xo 1 thì dãn 2cmTreo dưới lò xô 2 thì dãn 3cm A. Ghép nối tiếp 2 lò xo rồi treo vật m vào dưới hệ thì dãn bài nhiêu B.ghép sống song 2 lò xo rồi treo vật m vào dưới thì hệ dãn bao nhiêu
Cho tam giác abc và điểm d trên cạnh ab sao cho ad =2/3_db qua d kẻ đường thẳng song song với bc cắt ac ở e A ,chứng minh rằng tam giác ade đồng dạng tam giác abc tính tỉ số đồng dạng B, tính chu vi của tam giác ade biết chu vi tam giác abc=60cm
Cho 10 gam hỗn hợp gồm Cu, Fe vào dung dịch HCl 20% (vừa đủ). Phản ứng kết thúc thu được 2,24 lít khí H2 (đktc). a. Viết phương trình hóa học. b. Tính khối lượng mỗi kim loại có trong hỗn hợp ban đầu. c. Tính khối lượng dung dịch HCl đã dùng cho phản ứng.
cho: S:= 0 ; n:=0 ; While S<= 30 do begin n:=n+1 ; S:= S+n end; Tính S???
cho hình thang vuông ABCD ( A^=D^=90°) , các đường chéo AC và BD vuông góc với nhau tại H . biết AH = 36Cm,HC = 64Cm A. Tính DH, HB B. Tính diện tích hình thang ABCD
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