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hatmyt1994
2 năm trước
Trình bày khái niệm, cấu tạo, quá trình truyền XTK qua xinap? Tại sao quá trình truyền tin qua xinap chỉ diễn ra theo 1 chiều?
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Giúp mik với Hứa vote 5* cho bn làm tốt Exercise 3: Read and answer the questions ( Đọc đoạn văn và trả lời các câu hỏi ). My last Sports Day occurred on the 8th of September in 2016. On that day, the school was beautifully decorated with colorful flags. Parents were invited to watch their children participate in many events. In the morning, our class was divided into four groups and they competed against one another. The children used balls, hoops, skipping-ropes and bags in the competition. The parents cheered them very much. In the afternoon, we had more interesting events. The Upper Primary students competed in many sports such as hurdles, relay races, short distance races, high jump and long jump. Every participant tried their best to win as many trophies as possible for their team. The prize-giving ceremony marked the end of the exciting day. The winners were cheered and carried on their classmates’ shoulders. Though we were very tired, we had enjoyed ourselves very much. 1. When did her last Sports Day take place? __________________________________________________________________ 2. What was the school decorated with? __________________________________________________________________ 3. Who were invited to watch her children participate in many events? __________________________________________________________________ 4. What did the children use in the competition? __________________________________________________________________ 5. What sports did the Upper Primary student compete in? __________________________________________________________________ 6. Why did the participants try their best? __________________________________________________________________ Exercise 4: Read again and decide if each statement is true (T), false (F) or not given (NG). Đọc lại đoạn văn và quyết định xem câu nào đúng, câu nào sai hoặc không đưa ra) 1. This seemed to be a high school. _____________ 2. The teachers also took part in the Sports Day as participants. _____________ 3. The author’s class was divided into four teams. _____________ 4. There were not any individual events in this Sports Day. _____________ 5. The Day was marked with prize-giving ceremony. _____________ 6. Everybody didn’t enjoy the Day too much as they were so tired. _____________

1.My life is extremely terrible. I ___________ anything . A. have B. haven’t got C. have got D. A&C correct * 2. It takes me 15 minutes_________to school from home. A. to go B. going C.go D. to going * 3. Maria: “I’ve passed all my exasminations.” – Linda: “___________” A. Good luck! B. No problem C. That’s a good idea D. Congratulations! * 4. How often do you visit your friends ? ___________ A. sometime B. never mind C. I don’t like D. I’d love to 5 I couldn’t find your number in the telephone _______. A. dictionary B. brochure C. notebook D. directory * 6. I don’t always _______ perfume, but this is a special occasion. A. put B. spray C. spend D. wear * 7. Joan_______ an orange leather handbag on her left hand. . A.is making B. is showing C. is taking D. is carrying * 8. When you take part in a competition, you are called a _______ . A. gentleman B. lady C. competitor D. singer * 9.Julia is wearing a_______ , and a black nylon skirt. A.white blouse cotton B. white cotton blouse C. blouse white cotton D. cotton white blouse * 10. I don’t like films very much. So, I _______go to the cinema. A. usually B. sometimes C. always D. rarely * 11. It’s too dark. Why don’t you turn the light _______ . A. up B. on C. off D. out * 12.This is the most expensive book I have _______ bought . A. never B. not C. ever D. always * 13_______ does he go jogging? - Twice a week A. How B. How long C. How about D. How often * 14.Be silent, please! The teacher_______ to my mother. A. talked B. has talked C. is talking D. talks * 15.Are there_______ students in the classroom? A. a B. any C. some D.an * 16. She ______ to work everyday . A. is walking B. will walk C. walks D. was walking * \ 17. Turn back later please. My boss______ in his office now. A. is working B. works C. has worked D. will work * 18. Eliza is a teacher. She ______ English to young children .A. sings B. tells C. teaches D. speaks * 19. Would you like ______ with us to the countryside on the weekend? A. joining B. to join C. is joining D. joins * 20.There is ______ monosodium glutamate (bột ngọt) in the box. A. a little B. few C. a few D. many * 21. The Smiths never___________to their neighbors A. Talk B. talks C. don’t talk D. doesn’t talk * 22.The train ___________at 6 am tomorrow. A. Leaves B. leave C. is leave D. don’t leave * \ 23___________ is the first person who walked on the Moon. A.Neil Alden Armstrong C. Columbus B.Alexander Graham Bell D. John Logie Baird * \ 24. My feet were killing me. I find going around art galleries and museums really________ . A. exhausting B. boring C. exhausted D. bored * 25. His daughter is interested in _______ the cartoon . A. to watch B. watch C. watching D. watched *

Năm 2002, giáo sư Ekhard Wimmer (Anh) đã tiến hành tổng hợp nhân tạo được genom ARN (+) của virus bại liệt rồi đưa vào tế bào để cho chúng nhân lên. Khi tiêm các virus bại liệt nhân tạo này vào chuột thì chuột cũng bị bệnh bại liệt. Gần đây, một nhà khoa học trẻ đã tách được genom của virus cúm A/H5N1 gồm 8 phân tử ARN (-), rồi đưa genom tinh khiết này vào nhân của tế bào niêm mạc đường hô hấp của gia cầm với hi vọng sẽ thu được kết quả giống như của giáo sư E. Wimmer. Hãy phân tích 2 thí nghiệm này và trả lời các câu hỏi sau: a) Tại sao thí nghiệm của E. Wimmer lại thành công? b) Thí nghiệm của nhà khoa học trẻ có tạo ra được virus cúm A/H5N1 không? Giải thích.

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