Cho hình thang ABCD có hai đáy là AB và CD. Gọi M là trung điểm của CD, E là giao điểm của MA và BD, F là giao điểm của MB và AC a)c/m EF//AB b) Đường thẳng EF cắt AD, BC lần lượt tại M, N. Chứng minh: ME = EF = FN c) Biết AB = 7,5cm, CD = 12cm. Tính MN.

Tìm max -2x^2 - 4x - 3 -x^2 - 1x - 2

d,5x+10/4x-8.4-2x/x+2 Bài 2: rút gọn a, 6x ² y ³/8x ³y ² b, x ³-x/3x+3 c, x ²+3xy/x ²-9y ² d, x ²+4x+4/3x+6

Nếu coi không khí chứa N2 hoặc O2 có tỉ lệ tương ứng là 1:4 về thể tích thì khối lượng của 22,4 lít không khí ở điều kiện tiêu chuẩn là bao nhiêu gam ?

Ở đậu Hà Lan, alen A quy định quả màu lục trội hoàn toàn so với alen a quy định quả màu vàng. Theo lí thuyết, phép lai nào sau đây cho đời con có tỉ lệ kiểu hình là 3 cây quả màu lục : 1 cây quả màu vàng? A: AA × aa. B: AA × Aa. C: Aa × aa. D: Aa × Aa.

III Rewrite the following sentences without changing their meaning. 1. What a pity! She isn’t here with us. -> I wish …………..…………………………………………………………………. 2. How long have you bought this car? -> When ……………………………………………………………………………… 3. Does your father go to work at 6.00 every day? -> Your father …………………………………………………………………….? 4. “I must go tomorrow” , he said. -> He said……………………………………………………………………… 5. You should pay your bill before you leave the hotel. -> Your bill …………………………………………………………………….. 6. “Will you be free tomorrow ? ”. She said.  She asked me……………………………………….. 7. What a pity ! I can’t go camping with you .  I wish…………………………………………………… 8. “ What is your mother doing now ?”. The teacher asked.  The teacher asked Tom……………………………………………… 9. They have built a new bridge in this area.  A new bridge…………………………………………………………… 10. I missed you , so I phoned you more often .  Because……………………………………………………………

Số vòng của cuộn dây sơ cấp và thứ cấp của máy biến thế lần lượt là:3300 vòng và 150 vòng. Hỏi hiệu điện thứ giữa hai đầu cuộn thứ cấp là bao nhiêu? Biết hiệu điện thế giữa hai đầu cuộn sơ cấp là 220V

Tục ngữ quan niệm như thế nào về con người và giá trị của con người ?

Complete the sentence so that it has a similar meaning to the first. 1. The exam question was so easy that we all got it right. It was ___________________________________________________________ 2. Although he wasn’t experienced, he got the job. Despite __________________________________________________________ 3. Walking home alone is not a good idea. You______________________________________________________________ 4. “Did someone ring you an hour ago?” - Martin said to Susan. Martin asked ______________________________________________________ 5. Nigel hasn’t got a satellite TV, so he can’t watch the game. If _______________________________________________________________

Mark the letter A, B,C or D on your answer sheet to indicate the correct answer to each of the following questions. Question 7. I wonder who live ________ , country folk or city people? A: happilier B: more happily C: more happier D: happier 2 choose the correct sentence A, B, C or D. A: More industry and automobiles are concentrated in urban areas than in rural areas. B: More industry and automobiles is concentrated in urban areas that in rural areas. C: More industry and automobiles is concentrated in urban areas than in rural areas. D: More industry and automobiles are concentrated in urban areas that in rural areas. 3 Mark the letter A, B, C or D on your answer sheet to indicate the word whose underlined part differs from the other three in pronunciation in each of the following questions. A: close B: clog C: clock D: cloth 4 Mark the letter A, B, C or D on your answer sheet to indicate the word that differs from the other three in the position of primary stress in each of the following questions. A: quiet B: friendly C: nomadic D: peaceful 5 Mark the letter A, B,C or D on your answer sheet to indicate the correct answer to each of the following questions. Question 12. Be quiet! The baby ____________ . A: is sleeping B: aren’t sleeping C: are sleeping D: isn’t sleeping 6 Mark the letter A, B,C or D on your answer sheet to indicate the correct answer to each of the following questions. Question 11. Yesterday evening I watched a ________ . It was so scary that I couldn’t sleep at night. A: comedy B: thriller C: news D: play 7 Mark the letter A, B, C or D on your answer sheet to indicate the word whose underlined part differs from the other three in pronunciation in each of the following questions. A: decided B: rented C: prevented D: looked 8 choose the correct sentence A, B, C or D. A: In the countryside, the life style is not so fast as the life style in cities. B: In the countryside, the life style is less faster than the life style in cities. C: In the countryside, the life style is faster than the life style in cities. D: In the countryside, the life style is more faster than the life in cities.