-Vận tốc truyền âm của môi trường ko khí: 340m/s
-Vận tốc truyền âm của môi trường nước:1500m/s
-Vận tốc truyền âm của môi trường thép:6100m/s
⇒Không khí<Nước<Thép
Vận tốc truyền âm của môi trg :
- không khí : 340 m/s.
- nước : 1500 m/s.
- thép : 6100 m/s.
So sánh vận tốc truyền âm (từ bé đến lớn) : không khí - nước - thép.
1. She has arranged to work this afternoon, so she can't come shopping with us. => (NOT) Had ________________ this afternoon, she would have been able to come shopping with us. * 2. Someone has stolen my bike, Dad. => (HAD) I ____________________, Dad. * 3. People expect that the weather will change soon. => (TO) The weather _______________ soon. * 4. I wouldn't mind contacting her but I don 't have her phone number. => (WOULD) I _________________ if I had her phone number. * 5. When did they replace the broken windows, Annie? => (REPLACED) When _______________________, Annie? * 6. You are all welcome to have some more cake. => (HELP) Feel free to __________________ some more cake. * 7. Chris, I shall be glad to show you round if you decide to visit London. => (SHOULD) Chris, ____________________ to visit London, I shall be glad to show you round. * 8. We 've asked an electrician to install lights in the garden. => (HAVE) We will ____________________ lights in the garden. * 9. If she doesn't follow a stricter diet, she won't lose any weight. => (UNLESS) She won't lose any weight __________________ a stricter diet. * 10. I wouldn't have succeeded if my parents hadn't encouraged and supported me . => (BUT) I wouldn't have succeeded _________________________ and support. *
mn giúp mk vs aj mình cho vote 5 sao
trả lời câu sau - What type of house will it be ? - How big will it be ? - What will there be in front and behind it ? - What will it have ? Cảm ơn các bạn
20. Windows are used to let in light and _______ out cold. a. to keep b. keep c. keeping d. for keeping 21. It isn't worth while_______ her. a. marry b. to marry c. marrying d. to have married 22. She did nothing but_______ a. cry b. to cry c. to have cried d. crying 23. He can’t live without_______ here. a. being loved b. to love c. love d. loving 24. People are prevented from_______ to the polluted area. a. go b. going c. to go d. to have gone 25. Tourists are not allowed _______ in the Temple. a. to talk b. talk c. talking d. being talked 26. The teacher doesn't allow_______ dictionaries in the final examination. a. being used b. use c. using d. to use 27. The president agreed_______ the Agreement. a. to sign b. sign c. signing d. to have signed 28. He tried to avoid_______ my question. a. answer b. answering c. to answer d. to have answered 29. Paula has given up _______ to lose weight. a. try b. trying c. to try d. to have tried 30. We can't go on_______ like this. a. living b. live c. to live d. to be living 31. Don't keep_______ me while I'm talking. a. interrupt b. to interrupt c. interrupting d. to have interrupted 32. I can't imagine Bill _______ a motorbike. a. ride b. riding c. to ride d. to be riding 33. Sorry to keep you_______ so long. a. waiting b. wait c. to wait d. to have waited 34. She now regrets_______ it. a. say b. having said d. to say d. to have said 35. We decided_______ at home. a. to stay b. stay c. staying d. having stayed 36. Frank tends_______ too much. a. to have drunk b. drinking c. drink d. to drink 37. He doesn't want_______ a. to know b. know c. knowing d. to be knowing 38. I don’t advise anybody_______ in that hotel. a. stay b. to stay c. staying d. to have stayed 39. The mother made her child_______ the word a. repeat b. to repeat c. repeating d. to be repeating 40. My parents don't let me_______ out alone. a. go b. to go c. going d. to be going
GIÚP em với ạ em đang cần gấp câu này ạ
........................................................
Cho A là 1 loại phân đạm chứa 6,67%H,46,66%N còn lại là cacbon và oxi.đốt cháy 1,8g A thu dc 0,672 lít CO2 ở dktc.Xác định cthh A bt rằng kl N2 có trong 1 mol <Kl N2 có trong 100g NH4NO3
Làm giúp tớ câu d và câu e thôi ạ Cảm ơnnn các cậu
Choose the letter A, B, C or D to indicate the word whose underlined part is pronounced differently from that of the rest. A. rewrite B. reuse C.recycle D.resident 9 Choose the letter A, B, C or D to indicate the sentence that is CLOSEST in meaning to the original. My house has a living room, a bed room and a kitchen. A. There are a living room, a bedroom and a kitchen in my house. B. There has a living room, a bedroom and a kitchen in my house. C. There is a living room, a bedroom and a kitchen in my house. D. My house there is a living room, a bedroom and a kitchen. 10 Choose the letter A, B, C or D to indicate the odd one out from the rest. A. weatherman B. channel C. MC D. TV viewer 11 Choose the letter A, B, C or D to indicate the best answer to the following question. If we _______________ soil pollution, we___________ enough food to eat A. reduce/ won’t have B. reduce/ will have C. don’t reduce/ will have D. will reduce/ have 12 Choose the letter A, B, C or D to indicate the most meaningful sentence written from the given words. I/ could/ play/ chess/ when/ I/ six. A. I could play chess when I was six. B. I could play chess when I were six. C I could play chess when I am six. D. could playing chess when I was six. 13 Choose the letter A, B, C or D to indicate the underlined part that needs correction of the following question. The black car is more cheaper than the red one. a The B. cheaper C. more D. is 14 Choose the letter A, B, C or D to indicate the most suitable response to complete the following exchange. Tom: “Would you like to visit Ha Long Bay?” Nick: “_________________” A. Thank you very much B. Yes, I’d love to C. Yes, I like it very much D. No, I don’t
Giúp mình câu a và c với ạ. Mình cảm ơn nhiều ạ
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