Cho (O;R) và điểm A cố định sao cho OA = 2R. Từ A kẻ 2 tiếp tuyến AB, AC và cát tuyến AMN với đường tròn (B ,C, M,N thuộc đường tròn và AM < AN). Gọi D là trung điểm của MN ; CD kéo dài cắt (O) tại E. a) 5 điểm A, B, O ,D ,C cùng nằm trên 1 đường tròn b) OA vuông góc BC tại H và tính S tam giác OBC c) BE // MN Giúp mình với

Đạo hàm các hàm số sau: a. `y=4tanx-cosx+4x^3+2\sqrt[x]` b. `y=-cosx-2cos2x+sin(4x-pi/3)` c. `y=sin2x+2cos4x` d. `y=sinx^2+sin^2x`

Bài 47: Cho x + y = 5 tìm giá trị nhỏ nhất của biểu thức: A=|x+1|+|y-2| Bài 48: Cho x – y = 3, tìm giá trị của biểu thức: B=|x-6|+|y+1| Bài 49: Cho x – y = 2 tìm giá trị nhỏ nhất của biểu thức: C=|2x+1|+|2y+1| Bài 50: Cho 2x+y = 3 tìm giá trị nhỏ nhất của biểu thức: D=|2x+3|+|y+2|+2

Choose the best answer. 1.................to music is one of her favourite hobbies. A. Listen B. Is listening C. Listening D. Listened 2.I don’t like Maths ……………it is difficult. A. and B. but C.so D. because 3.What’s the matter…………you? A.in B. with C. on D. of 4. Do you like English? Yes, I………. A.do B.am C. like D. don’t 5. He often………………to school in the morning A. gos B. going C. goes D.to go 6. His birthday is ....................June 1st. A. at B. on C. in D. about 7. Does he ..................... a sore-throat? A. has B. had C. have D. having 8. We went to the cinema ...................... . A. today B. yesterday C. tomorrow D. next Sunday 9. A housewife often does .................... . A. homework B. housework C. hard work D. exercises 10. A: Thanks for your gifts , Jollie. B: ................................................ A. No problem B. Don’t worry C. You're welcome D. Excuse me

I.Supply the correct form of the verbs in the brackets: 1.They ( live )______ in London since 1980. 2.If it (be)_________ nice tomorrow , we (go)_______ on a picnic. 3.She (work)_______here for two years. 4.You must (learn)_______harder. 5.They might not (have)____a meeting next week. 6.The sun (warm)______the air and (give)______ us light. 7.They(not live)________in HaNoi from 1970 to 1999. 8.You (put)________your book on my desk last night ? 9.He (study)________English at this school now. 10.She (go )________to school everyday.

21. Jim was absent because he was ill. - Because of 22. We were late for the play because of the long line at the ticket-window. - Because there 23. I couldn’t see anything because it was so dark. - Because of 24. Because the weather is warm and damp, rice grows very well here. - Because of 25. Jane never says a hard word to Tom because of her love for him. - Because Jane __________________________________ 26. Nobody could solve this mathematical problem.  This 27. They believe that he will pass the final exam.  He 28. She was too old to carry that heavy case.  She was so 29. He seldom keeps his promise.  Seldom 30. I have never travelled by plane in my life.  Never 31. Jack is not old enough to see horror films.  Jack is too 32. You will catch cold if you don’t keep your feet dry.  Unless 33. People saw him leave the office yesterday.  He 34. She came late because of the rain.  Because it 35. “You’d better not lend them any more money.” said Alice.  Alice advised 36. She decided to help him with some money.  She made 37. We have to notice the teacher’s explanation.  We have to pay 38. This flower is very beautiful.  What 39. He spent 2 hours doing the mathematical exercises.  It took 40. They have to change the date of the meeting again.  The date . 41. It was so late that nothing could be done.  It was too 42. I didn’t go out because it rained.  If 43. I have fewer books than she has.  She has 44. Mary visited us three days ago.  Mary paid 45. The plumber repaired the leak this morning.  They had 46. Although he’s got an English name, he is in fact German.  Despite 47. I found a place to live but it was difficult.  I had difficulty 48. The book was so good that I couldn’t put it down.  They had 49. He’s fat because he doesn’t take any exercises.  But if 50. Turn off all the switches before leaving the workshop.  All the switches

5.Đặc điểm nào của bộ linh trưởng chứng tỏ chúng là thú tiến hóa nhanh nhất so với các bộ thú khác ? 6.Tại sao các loài thú móng guốc thường chạy nhanh?Kể tên các bộ móng guốc đã học và trính bày đặc điểm của từng bộ móng guốc ?

Căn cứ vào đặc điểm thế nào của thú để phân loại lớp thú . Trình bày sơ đồ tư duy sơ luộc phân loại thú ?

Dựa vào các đặc điểm của bộ răng phân biệt 3 bộ thú : bộ ăn sâu bọ , bộ gặm nhấm , bộ ăn thịt ?

Matching. A B 1. Hi, Lan. What are you doing? a. I’m reading a book about Santa Claus. 2. What are you reading? b. No, it isn’t. 3. Is it interesting? c. I don’t know what to do. Can you tell me? 4. Why don’t you do anything more interesting? d. Yes. That’s a great idea. 5. Let’s play football. e. I’m reading.