Cho tứ diện OABC có OA, OB, OC đôi một vuông góc và OA = OB = OC = 1 . Tính góc giữa hai đường thẳng BC và OM

cho tam giác ABC trung tuyến AD. Đường phận giác của góc ADB cắt cạnh AB ở M .đường phận giác của góc ADC cắt cạnh AC. Ở N /A) chứng minh rằng MN sống song với BC /b) gọi k là giáo điểm của AD và MN .chứng minh K là trung điểm của MN /c) chứng minh AM.AC-AB=0

Điều tra số tuổi nghề (tính theo năm) của một số công nhân trong một phân xưởng được ghi lại ở bảng số 7 7 8 7 8 8 6 4 5 4 8 8 3 6 7 6 5 7 7 3 6 4 4 6 6 8 6 6 8 8 liệu sau a) Dấu hiệu ở đây là gì ? Số các giá trị là bao nhiêu ? b) Lập bảng “tần số” mn giúp mik vs ạ , mik hứa sẽ cho ̀ sao , câu trả lời hay nhất và cảm ơn , giúp mik vs

Chia động từ trong ngoặc ở câu đk loại 1 1. If I .......... ( not/ have) lunch, I.......... (be) hungry. 2. If he ......... ( not/ be) at work, he.......... (be) at home then. 3. If I ........... ( not/ work), I ........ (go) to a discon. 4. If Oanh ......... ( not/ be) thirsty, she ........... ( not/ drink) any fizzy mineral water. 5. If she ........( not/get) friend, I .......... ( invite) her to our party. 6. If they ......... ( not/ communicate), they ......... ( not/have) any Jobs. 7. If my daughter ( not / do ) the washing up, I......... ( have / to) do it instead of her. 8. I ......... (not/tell) anybody about it If you....... ( not/want). 9. I am sure she ....... (to/do) it if you........ (to ask ) her. 10. They ........( come ) if she ....... (invite) them. 11. He ......... (wirte) a letter to her if she......... ( wirte) first. 12. I ......... (go) there if you........ (go) with me. 13. Max ....... (pass) the exam if he .........( study) hard. 14. If he ......... (not/ be) at home, I......... (visit) his sister then. 15. If she ........... ( not/walk) every day, she....... (not/be) healthy enough. 16. If Max ....... ( not/ accept) Alex's invitation this time, Alex........ (not/invite) him again. 17. If my kid ....... (not/ read) this book, he ........ (not/get) a good mark in Literature. 18. If Tom ........ (not/water) the violets, they ........ (die) 19. If Lena ........ (not/be) happy, she ........ (not/stay) there for a long time. 20. If my son ........ (not/ make) his bed, he ........ (not/play) football with his friends. 21. If my teacher ........ (not/like) my English, I ........ (try) so study it harder than before. 22. My son ........ (speak) English fluently if he ........ (go) to study English a broad. 23. If she ........ (fall) in love with Henry, they ........ (get) married, I think. 24. If you ........ (hepl) me, I ........ (help) you. 25. If they ........ (catch) the bus,they ........ (arrive) on time. 26. If my parents ........ (support) me I ........ (be) a better person. 27. If it ........ (rain) , I ........ (get) wet. 28. Sally and Elizabeth ........ (go) out to night if their parents ........ (allow) it. 29. They .......... (visit) Eiffel Tower if they ........ (go) to Erance. 30. If I ........ (pass) the year, my parents ........ (give) me a gift. 31. If I ........ (not / pass) the year, my parents ........ (be) very disappointed. 32. If the cable TV ........ (not/work), we ........ (rent) a DVD. 33. If I the baby ........ (not/eat) , we ........ (see) the doctor. 34. If the T - shirt ........ (suit/me) , I ........ (buy) it. 35. If you ........ (coninue) on a diet, you ........ (get) sick. 36. If you ........ (be) a good listener, you ........ (have) many friends. 37. If you ........ (not/be) careful, you ........ (spoil) the machine. 38. If she ........ (not/be) careful, she ........ (not/have) enough money left. 39. If you ........ (get) enough sleep, you ........ (feel) healthier. 40. My parents ........ (give) me a hug, If I ........ (arrive) home early. 41. If you ........ (not/be) careful, you ........ (fall). 42. If she ........ (eat) that mayonnaise, she ........ (be) sick. 43. If they ........ (not/behave),thier parents ........ (punish) them. 44. She ........ (go) on a trip if she ........ (have got) holidays in August. 45. I ........ (get) dehydrated if you ........ (not/drink) morr water. 46. If it ........ (be) too much heat, I ........ (turn off) air conditioning. 47. You ........ (understand) conditional sentences if you........ (paractise) carefully. 48. We (do) ........ this for you if you want. 49. If we (need) ........ some help, we will ask. 50. If Peter stays with his grandparent, suson (not be) ........ happy. 51. If we win the money, we (buy) ........ a new house. 52. She (not write) ........ to you if she leaves. 53. We (go) ........ on holiday if there is time. Giải giúp mk với mk hứa vote cho 5*

Em muốn anh giải hết giùm em ạ

III/ EXERCISE I. Choose the best answer in brackets to complete each of the following sentences. 1. Yesterday I met some people_________ (who/ whose) car broke down. 2. What’s the name of the girl________ (who/ whose) is singing on the stage? 3. We went to Hoan Kiem to see firework___ (despite/ though) the fact that it’s very cold. 4. I sent a card to congratulate Hoa (for/ on) winning the first prize in the contest. 5. Minh _________(washed/ was washing ) the dishes while her sister ________(made/ was making) the cake. 6. All the things______ (who/ which) we bought are for the party on the New Year’s Eve. 7. _________ (In spite of/ Even though) I had an umbrella, I got very wet in the rain. II. Combine each pair of sentences into one by using a suitable Relative Pronouns. 1. Have you ever spoken to the people? They live next door. …………………………………………………………………………………………… 2. It’s a book. It will interest children of all ages. …………………………………………………………………………………………… 3. The people keep having all night parties. They live next door. …………………………………………………………………………………………… 4. These are the keys. They open the front door and back door. …………………………………………………………………………………………… 5. Here’s an article. It might interest you. …………………………………………………………………………………………… 6. Where are the eggs? They are in the fridge. …………………………………………………………………………………………… 7. Have you got something? It will get ink out of the carpet. …………………………………………………………………………………………… 8. Where’s the girl? She sells the tickets. …………………………………………………………………………………………… 9. Half of the people didn’t appear. They were invited. …………………………………………………………………………………………… 10. The festival is called Easter. It is in the late March or early April. …………………………………………………………………………………………… III. Combine each pair of sentences into one by using a suitable Relative Pronouns. 1. Have you ever spoken to the people? They live next door. …………………………………………………………………………………………… 2. It’s a book. It will interest children of all ages. …………………………………………………………………………………………… 3. The people keep having all night parties. They live next door. …………………………………………………………………………………………… 4. These are the keys. They open the front door and back door. …………………………………………………………………………………………… 5. Here’s an article. It might interest you. …………………………………………………………………………………………… 6. Where are the eggs? They are in the fridge. …………………………………………………………………………………………… 7. Have you got something? It will get ink out of the carpet. …………………………………………………………………………………………… 8. Where’s the girl? She sells the tickets. …………………………………………………………………………………………… 9. Half of the people didn’t appear. They were invited. …………………………………………………………………………………………… 10. The festival is called Easter. It is in the late March or early April. …………………………………………………………………………………………… IV. Use “ALTHOUGH”, “ THOUGH” or “ EVEN THOUGH” to combine each pair of these sentences. 1. He often tells lies. Many people believe him. …………………………………………………………………………………………… 2. She didn’t eat much. She was hungry. …………………………………………………………………………………………… 3. He is over 60. He doesn’t wear glasses. …………………………………………………………………………………………… 4. It got dark. They continued to work. …………………………………………………………………………………………… 5. She kept on studying. It was noisy. …………………………………………………………………………………………… 6. He ate all the fruits. They were green. …………………………………………………………………………………………… 7. We could do the test. It was very difficult. …………………………………………………………………………………………… 8. He is very strong. I’m not afraid of him. …………………………………………………………………………………………… 9. The plane took off. The weather was bad. …………………………………………………………………………………………… 10. He didn’t stop his car. The traffic lights turned red. …………………………………………………………………………………………… 11. They went on a picnic. The weather was very bad. …………………………………………………………………………………………… V. Combine each pair of sentences into one by using a suitable Relative Pronouns. 1. Have you ever spoken to the people? They live next door. …………………………………………………………………………………………… 2. It’s a book. It will interest children of all ages. …………………………………………………………………………………………… 3. The people keep having all night parties. They live next door. …………………………………………………………………………………………… 4. These are the keys. They open the front door and back door. …………………………………………………………………………………………… 5. Here’s an article. It might interest you. …………………………………………………………………………………………… 6. Where are the eggs? They are in the fridge. …………………………………………………………………………………………… 7. Have you got something? It will get ink out of the carpet. …………………………………………………………………………………………… 8. Where’s the girl? She sells the tickets. …………………………………………………………………………………………… 9. Half of the people didn’t appear. They were invited. …………………………………………………………………………………………… 10. The festival is called Easter. It is in the late March or early April. ……………………………………………………………………………………………

Giúp tớ sắp nộp rồi bài 4 thôi nha

Tính diện tích hình bình hành có độ dài hai đáy lần lượt là 34 cm 0,5 m Tom tat

làm phần bt vận dụng giúp mik nha

Mấy anh chị giúp em nhà yêu mọi người