Cho biết 3 người làm cỏ một cánh đồng hết 8 giờ. Hỏi 12 người làm cỏ cánh đồng đó hết bao nhiêu thời gian? (Năng suất lao động của mỗi người như nhau)

S (r) + O2 (k) --> P (r) + O2 (k) --------> C (r) + O2 (k) --------> Fe (r) + O2 (k) -------->

giúp vs ạ, cần gấp lắm, toán số :((((

Đường tròn (C) có tâm i và bán kính R đi qua 3 điểm (2;6),(1;5),(5;5). Phép đối xứng trục 3x-4y=m biến đường tròn (C) thành đường tròn (T) tâm K. Tính tích các giá trị m xảy ra khi IK=R A.-2.5. B.-15,-25. C. -18,5. D.20.25 Cao nhân nào giải hộ tui với 🙏

Find a mistake in the four underlined parts A, B, C or D of each sentence. Câu 42: Fish is one of my favorite sports. A B C D Câu 43: By the time he arrived, all his classmates left. A B C D Câu 44: Mary plays the piano when she was young. A B C D Câu 45: Mary likes watch the film Titanic. A B C D

Mọi người giúp em bài này với ạ

My sister went to Ha Noi _________. A. last week B. yesterday C. a week ago D. All are correct 33. She chooses _________career because she loves children. A. teaching B. teach C. teacher's D. teacher 34.I hope _________to university next year. A. will go B. going C. to go D. go 35._________do you often go to school? - At 6.30 every morning. A. With whom B. What time C. Who D. How 36. When I was young, I received some ……..training from my father. A. science B. scientist C. scientific D. scientifically 37. Nowadays, more and more young people want to have a university …… . A. educate B. educator C. educational D. education 38. In the 19th century, it was ………… for a woman to become a doctor. A. unable B. impossible C. couldn’t D. incapable 39. I was late for school this morning because my alarm clock didn’t ……… A. go off B. go on C. go away D. go up 40. Marie Curie was …......…..the Nobel Prize in chemistry for determining the atomic weight of radium. A. won B. dedicated C. devoted D. awarded 41. He took …………the position that his father had obtained at the college. A. on B. to C. in D. up

một xe đang chuyển động với vận tốc 5m/s bắt đầu chuyển động thẳng nhanh dần đều theo phương nằm ngang sau 12 phút xe đạt 54km/h. tính vận tốc xe đạt được tại thời gian 8 phút kể từ lúc xuất phát.

bài này làm kiểu j để còn làm bài tập thầy giao hay chỉ cho tôi mai nộp bài tạp

They either read stories _______ play games. a. and b. or c. nor d. not 17. He ____ for London one year ago. A. left B. has left C. leaves D. had left 18. I ____ to the market with my mother yesterday. A. go B. went C. have gone D. was going 19. How long ____ you ____ her? – For five months. A. do/know B. are/knowing C. have/known D. had/known 20. I usually ____ to school by bus. A. went B. am going C. go D. have gone 21. Yesterday morning I ____ up at 6.30. A. got B. get C. was getting D. had got 22. Water ____ at 100 degrees Celsius. A. boils B. boiled C. is boiling D. will boil 23. ____ you ____ out last night? A. Did/go B. Do/go C. Have/gone D. Were/going 24. This house ____ 35,000 pounds in 1980. A. costs B. cost C. had cost D. was cost 25. Mike is playing chess. How long ____ he ____? A. did/play B. is/playing C. has/play D. has/been playing 26. After they ____ their breakfast, they ____ shopping yesterday. A. have/go B. had had/go C. had/had gone D. had had/went 27.We sometimes visit our neighbours for a cup of tea. A. come in B. come to see C. come on D. come away 28.I've been in this city for a long time. I _________here sixteen years ago. A. come B. am coming C. came D. have come 29. It's better to avoid _________during the rush hour. A. to travel B. travelled C. travelling D. travel 30.Nam _________his hair cut twice a month. A. is having B. will have C. have D. has