21. About 15,000 years ago, northern Wisconsin ______ under ice a mile deep. A. buried B. was burying C. was buried D. had buried 22. Edward was new on the job, but he quickly fit himself into the ______ routine of the office. A. established B. establishing C. establishes D. establish 23. The Mayan Indians ______ an accurate and sophisticated calendar more than seven centuries ago. A. were developed B. developed C. are developed D. have been developed 24. George is ______ Lisa. A. marry with B. marry to C. married with D. married to 25. The rescuers ______ for their bravery and fortitude in locating the lost mountain climbers. A. were praised B. praised C. were praising D. praising 26. When I woke up and looked outside, the landscape had changed. The ground had been lightly ______ with a dusting of snow during the night. A. covering B. cover C. covers D. covered 27. We can't even walk in the storm. Let's wait in the hallway where we'll be ______ the strong winds until things quiet down. A. protected from B. protected by C. protecting from D. protecting by 28. "______ about the eight o'clock flight to Chicago?" - "Not yet. " A. Has been an announcement made B. Has an announcement made C. Has an announcement been made D. Has been made an announcement 29. Last night a tornado swept through Rockville. It ______ everything in its path. A. destroyed B. was destroyed C. was being destroyed D. had been destroyed 30. Be sure to wash the vegetables throroughly. A lot of pesticide residues ______ on unwashed produce. A. can find B. can found C. can be found D. can be finding

giúp mk nha giải thích nx thanks nhìu

11. "The longest fish in the contest was eighteen inches long. " - "It ______ by Peter. " A. was catching B. caught C. was caught D. catch 12. "I heard you decided to take up tennis. ” - "Yes, I have ______ every day. " A. been played B. been playing C. playing D. play 13. "Are we about to have dinner?" - "Yes, it ______ in the dining room. " A. is serving B. serves C. is being served D. served 14. "Why is Tony in prison?" - "He ______ of robbery. " A. has been convicted B. has been convicting C. has convicted D. convicted 15. "Where are Jack and Joseph?" - "They ______ the boxes you asked for into the house. " A. have been bringing B. bringing C. have been brought D. to bring 16. "Where's the old chicken coop?" - "It ______ by a windsorm last year. " A. destroy B. is destroyed C. was destroyed D. destroyed 17. "We're still looking for Tom?" - "Hasn't he ______ yet?" A. been found B. to find C. found D. being found 18. "Whatever happened to that fortune-teller?" - "I don't know. She ______ around here in a long time. " A. hasn't seen B. didn't see C. hasn't been seeing D. hasn't been seen 19. "Diana is a wonderful ballet dancer. " - "She ______ since she was four. " A. has been dancing B. has been danced C. is dancing D. was danced 20. "What a beautiful dress you're wearing!" - "Thank you. It ______ especially for me by a French tailor. " A. is made B. has made C. made D. was made

làm bài cho mk 5* và trả lời hay nhất

Các cậu giải thích và làm giúp mình nhé

Dãy chất chỉ gồm các oxit axit là: A. CO, CO2, CaO, Al2O3, N2O5 B. SO3, SO2, MnO, Fe2O3, N2O5 C. FeO, Mn2O7, SiO2, CaO, Fe2O3 D. N2O5, CO2, P2O5, SO2, SiO2

Choose the best answer for the following sentences: 1. "Those eggs of different colors are very artistic. " - "Yes, they ______ in Russia. " A. were painted B. were paint C. were painting D. painted 2. "David is in prison for smoking drugs. " - "He ______ that it was against the law. " A. is telling B. was told C. told D. tells 3. "The maintenance people didn't remove the chairs from the ballroom. " - "Don't worry. They ______ them before the dance begins. " A. will have been moved B. will have moved C. were moved D. moved 4. Gold ______ in California in the 19th century. A. was discovered B. has been discovered C. was discover D. they discovered 5. ______ that military spending is extremely high. A. We are left B. It feels C. It is felt D. We feel that it is 6. All planes ______ before departure. A. will check B. will have checked C. will be checked D. will be checking 7. I wanted ______ by the head of the company, but it was impossible. A. to see B. to be seen C. seeing D. being to see 8. Nancy ______ at Bob's house every night this week. A. has been eaten B. has eating C. is being eaten D. has been eating 9. "Where did you get these old dresses?" - "We ______ them in the old trunk. " A. were found B. finding C. found D. have been found 10. "What happened to the old mail carrier?" - "He ______ to a new neighborhood to work. " A. has sent B. was send C. was sent D. sent

Giải phương trình sau: $\frac{1}{2x-2}$ -$\frac{2x+1}{x²+x+1}$ +$\frac{3}{2x+2}$ =0

Cho a,b,c>0 và a+b+c=4 Cmr (a+b)(b+c)(c+a) ≥(abc) ³

Người ta thả một quả cầu đồng chất vào bình chứa nước thì thấy thể tích cảu quả cầu bị ngập 90% khi ở trạng thái cân bằng biết TLR cảu nước là 10000N/m3 a. Xác định TLR cảu quả cầu b. Người ta tiếp tục đổ thêm dầu vào bình cho tới khi quả cầu bị ngập hoàn toàn, xác định tỉ số giữa phần thể tích của quả cầu bị ngập trong nước với thể tích của quả cầu ngập tro dầu. Khi quả cầu ở trạng thái cân bằng, biết TLR cảu dàu là 8000N/m3 bạn nào giúp mình giải ý b với ( ý a mình tính ra bằng 9000N/m3 không biết đúng không)