Help meeeeeeeeeeeeeeeeeeeeeee 800 từ nha

1. When I last saw him, he _____ in London. A. has lived B. is living C. was living D. has been living 2. We _______ Dorothy since last Saturday. A. don’t see B. haven’t seen C. didn’t see D. hadn’t seen 3. The train ______ half an hour ago. A. has been leaving B. left C. has left D. had left 4. Jack ______ the door. A. has just painted B. paint C. will have painted D. painting 5. My sister ________ for you since yesterday. A. is looking B. was looking C. has been looking D. looked 6. I ______ Texas State University now. A. am attending B. attend C. was attending D. attended 7. He has been selling motorbikes ________. A. ten years ago B. since ten years C. for ten years ago D. for ten years 8. Christopher Columbus _______ American more than 500 years ago. A. discovered B. has discovered C. had discovered D. had been discovering 9. He fell down when he ______ towards the church. A. run B. runs C. was running D. had run 10. We _______ there when our father died. A. still lived B. lived still C. was still lived D. was still living 11. They ______ table tennis when their father comes back home. A. will play B. will be playing C. play D. would play 12. By Christmas, I _______ for Mr. Smith for six years. A. will have been working B. will work C. have been working D. will be working 13. I _______ in the room right now A. am being B. was being C. have been being D. am 14. I ______ to New York three times this year. A. have been B. was C. were D. had been 15. I’ll come and see you before I _______ for the States. A. leave B. will leave C. have left D. shall leave 16. The little girl asked what _______ to her friend. A. has happened B. happened C. had happened D. would have been happened 17. John ______ a book when I saw him. A. is reading B. read C. was reading D. reading 18. He said he _______ return later. A. will B. would C. can D. would be 19. Jack ________ the door. A. has just opened B. open C. have opened D. opening 20. I have been waiting for you ______ . A. since early morning B. since 9 a.m C. for two hours D. All are correct 21. Almost everyone _______ for home by the time we arrived. A. leave B. left C. leaves D. had left 22. By the age of 25, he ______ two famous novels. A. wrote B. writes C. has written D. had written 23. When her husband was in the army, Mary ______ to him twice a week A. was reading B. wrote C. was written D. had written 24. I couldn’t cut the grass because the lawn mower ______ a few days previously. A. broke down B. has been broken C. had broken down D. breaks down 25. I have never played badminton before. This is the first time I _____ to play. A. try B. tried C. have tried D. am trying 26. Since _______, I have heard nothing from him. A. he had left B. he left C. he has left D. he was left 27. After I _______ lunch, I looked for my bag. A. had B. had had C. have has D. have had 28. By the end of next year, George _______ English for two years. A. will have learned B. will learn C. has learned D. would learn 29. The man got out of the car, ________ round to the back and opened the book. A. walking B. walked C. walks D. walk 30. Henry _______ into the restaurant when the writer was having dinner. A. was going B. went C. has gone D. did go 31. He will take the dog out for a walk as soon as he ______ dinner. A. finish B. finishes C. will finish D. finishing 32. I will be glad if he _______ with us. A. had gone B. did go C. went D. goes 33 Ask her to come and see me when she _______ her work. A. finish B. has finished C. finished D. finishing 34. Turn off the gas. Don’t you see that the kettle ________ ? A. boil B. boils C. is boiling D. boiled 35. Tom and Mary ______ for Vietnam tomorrow. A. leave B. are leaving C. leaving D. are left 36. He always ________ for a walk in the evening. A. go B. is going C. goes D. going 37. Her brother ______ in Canada at present. A. working B. works C. is working D. work 38. I ______ to the same barber since last year. A. am going B. have been going C. go D. had gone 39. Her father ______ when she was a small girl. A. dies B. died C. has died D. had died 40. Last week, my professor promised that he ________ today. A. would come B. will come C. comes D. coming

so sánh 2020 x 2018 + 1 / 2019 x 2019 và 1

Giúp t bài nay với mn please .tìm min max ạ

Hòa tan 15,3g BaO vào 200ml dd HCl7,3%(D=1,1g/ml).Xđịnh C% dung dịch nhận đc

2020 x 2018 + 1 / 2019 x 2019 Câu 9:

1. CM: Căn tất cả 6+căn 35 + căn tất cả 6-căn 35 2. Rút gọn Căn 125 - 4 căn 45 + 3 căn 20 - căn 80 5/4-căn 11 + 1/3+căn 7 - 6/căn 7 - 2 - căn 7 -5/ 2

Câu 3 (2 điểm): Có thể dùng hóa chất nào để phân biệt dung dịch HCl và dung dịch H2SO4 loãng? Câu 4 (2 điểm): Hoàn thành phương trình phản ứng hóa học sau:`Fe2O +CO -> (M)+(N)`. Câu 5 (2 điểm): Ống nghiệm (1) chứa 2 ml dung dịch HCl 1M. Ống nghiệm (2) chứa 2 ml dung dịch H2SO4 1M. Cho Zn dư vào hai dung dịch axit trên thì thể tích khí hidro thu được từ ống nghiệm (1) và (2) tương ứng là V1 và V2 đo ở cùng điều kiện. Viết phương trình hóa học. So sánh V1 và V2.

chứng minh rằng 1/1.2 +1/3.4+1/5.6+...+1/49.50=1/26+1/27+1/28+...+1/50

Dẫn từ từ 3,136 lít khí S02(đktc)vào 1 dung dịch có hòa tan 12,8 gam NaOH,sản phẩm là muối Na2S03.Viết PTPƯ/Chất nào còn dư,khối lượng là bao nhiêu/Xác định khối lượng muỗi thu được sau phản ứng