Cho tứ diện đều ABCD cạnh a. Diện tích của thiết diện cắt tứ diện ABCD bởi mặt phẳng chứa AB và vuông góc với CD là.

Chuyển mỗi câu chủ động sau đây thành hai câu bị động theo hai kiểu khác nhau. a. Nhóm tác giả viết xong cuốn sách trong gần một năm. b. Người ta tu sửa ngôi trường thật khang trang. c. Trận bão làm đổ những cây cổ thụ. d. Thầy giáo nhắc nó phải làm bài tập về nhà đầy đủ.

Cho hình vuông ABCD, trên cạnh AD lấy điểm M bất kì BE là tia phân giác góc MBC (E thuộc DC) CMR EC= MB-MA

Câu 1. Đốt cháy lưu huỳnh trong khí oxi, thu được 5,6 lít khí lưu huỳnh đioxit (đktc). a) Tính thể tích khí oxi tham gia phản ứng (đktc)? b) Nếu lượng oxi dùng cho phản ứng trên được điều chế từ KNO3¬ thì khối lượng KNO3 cần dùng là bao nhiêu? (Biết sơ đồ phản ứng KNO3 ----> KNO2 + O2) Vận dụng cao: Câu 2. Đốt cháy 3,2 gam lưu huỳnh trong một bình chứa 11,2 lít khí O2 (ở đktc). Thể tích khí SO2 thu được là: A. 4,48 lít. B. 2,24 lít. C. 11,2 lít. D. 3,36 lít. Câu 3. Cho 10,8 gam Al tác dụng với khí oxi thu được 10,2 gam Al2O3. Khối lượng khí oxi phản ứng là: A. 0,6 gam B. 4,8 gam C. 6,4 gam D. 9,6 gam Tự luận Câu 4. Đem hỗn hợp A gồm SO2 và O2 trong đó SO2 chiếm 50% số mol hỗn hợp A, cho qua chất xúc tác đun nóng, sau phản ứng thu được hỗn hợp B trong đó SO3 chiếm 35,29% số mol của hỗn hợp B. Tính hiệu suất của phản ứng.

một ô tô đi từ A dự định đi đến b lúc 9giờ30phút nhưng khi đi được 6km thì phải quay lại A và dừng lại đó 10 phút sau đó ô tô lại tiếp tục đi và đến b lúc 9giờ52phút tính vận tốc ô tô

Giải hộ em hpt của bài 2 em cảm ơn

A. Grammar: Too and Enough 1. It is too dangerous to walk home at this time of night. 🡪 It isn’t safe enough to walk home at this time of night. 2. The coffee is too cold for me to drink. 🡪 The coffee isn’t cool enough for me to drink. 3. Claire doesn’t want to marry Henry. She thinks he’s too young. 🡪 Claire doesn’t want to marry Henry. She thinks he isn’t _____ enough. 4. The trousers are too short for him to wear. 🡪 The trousers aren’t _______________ 5. These shoes are too small. 🡪 These shoes aren’t _______________ B. Practice I. Complete the sentences. Use too or enough with the words in brackets. 1. I couldn’t work. I was too tired. (tired) 2. Can you turn the radio up, please? It isn’t loud enough. (loud) 3. I don’t want to walk home. It’s ________________________________ (far) 4. Don’t buy anything in that shop. It _____________________________ (expensive) 5. You can’t put all your things in this bag. It _______________________ (big) 6. I couldn’t do the exercise. It ___________________________________ (difficult) 7. Your work needs to be better. It ________________________________ (good) 8. I can’t talk to you now. I ______________________________________ (busy) 9. I thought the film was boring. It ________________________________ (long) II. Give the correct form of the word in brackets. Example: My room is (small) 🡪 smaller than his room 1. Today Lien is (happy) ________________ because she misses her parents. 2. Trung’s new house is (big) ________________ than his old one. 3. They are (talk) ____________to the teacher. 4. There are thirty- six (class) ______________ in our school. 5. He doesn’t have many (relate) _______________ in Ha Noi. III. Choose the correct answer. Ann lives in London. She is twenty-nine and (0) B for the BBC. She interviews people on an early morning news program called the World Today. Every weekday she gets up at 3.00 in the morning because the program starts at 6.30. She loves (1) ________work because it is exciting and she meets a lot of very interesting people, but she loves her weekends, (2) ______ . On Fridays she comes home from the BBC at about 2.00 in the afternoon and she just (3) _________. On Friday evenings she (4) _________out, but sometimes a friend comes for dinner. He or she brings wine and they cook. Ann loves cooking. They (5) _____ music or just chat. On Saturday mornings she gets up a 9.00 and she goes (6) _________. Then in the evening she sometimes goes to the theater or the opera (7) _______ a friend- she loves opera. Then they eat in her favourite Chinese restaurant. On Sunday morning she stays in bed late. She doesn’t get up (8) ______ 11.00. Sometimes in the afternoon she visits her sister. She lives in the country and has two (9) ______. She likes playing with her niece and nephew, but she leaves early (10) _______ she goes to bed at 8.00 on Sunday evenings. 0. A. work B. works C. is work D. working 1. A. her B. she’s C. hers D. her’s 2. A. so B. too C. either D. and 3. A. relax B. relaxs C. relaxes D. relaxing 4. A. not goes B. isn’t go C. don’t go D. doesn’t go 5. A. listen B. hear C. listen to D. hear to 6. A. shop B. to shop C. shopping D. shops 7. A. to B. for C. of D. with 8. A. until B. to C. from D. on 9. A. child B. childs C. children D. childrens 10. A. and B. because C. or D. but IV. Write the correct tenses of the verbs in brackets. 1. How long you (know)…………………………………….Mrs. Chi? ~ I (know)……………………………….her for five years. 2. Your dog ever (bite)…………………………………anyone? ~ Yes, He (bite)……………………………..a policeman last week. 3. We (not/ see)………………………….her since we (be)……………………………..on holiday in Ha Long Bay. 4. Phuong Linh (not/ finish)………………………..her homework yet. 5. Would you like some coffee? I just (make)……………………………..some. 6. She (feed)…………………………the cat yet? ~ Yes, she (feed) ……………………….it half an hour ago. V. Rewrite the second sentence so that it has a similar meaning to the first one. Begin with the word(s) given. 1. It is not necessary for you to do the test. You __________________________________ 2. She couldn’t get to work because of the heavy snow. The heavy snow__________________________________ 3. I didn’t arrive in time to see her. I wasn’t early __________________________________ 4. The water was too cold for the children to swim in . The water wasn’t __________________________________ 5. I’ve never met such a famous person before. It’s __________________________________

cách đặc tâm thước đo độ đúng giải thích: ta xem 2 tia dao nhau ở chỗ nào thì ta đặt tâm thước đo độ chỗ đó hoặc 2 tia đó dao nhau cùng một điểm thì ta cũng đặc tâm thước đo chỗ 2 tia dao nhau cùng một điểm mình nói đúng không ạ xong mik vote 5 sao cảm ơn nhiều ạ giúp mik với

Giup mik cho 5 sao ai gioi toan nhe

III. Using the correct form of the verb in parentheses (Chia động từ trong ngoặc ở dạng đúng) (2,5 điểm) 1. A: It’s cold in here. Would you mind (close) ………….the window? B: Not at all. I’d be glad to. 2. A: It’s cold in here. Would you mind if I (close) ………….the window? B: Not at all. Go right ahead. I think it’s cold in here, too. 3. A: Do you mind (take) ………….the book back to the library for me? B: Not at all. 4. A: This story you wrote is really good. Do you mind If I (show) ………….it to my English teacher? B: Go right ahead. That’d be fine 5. A: I’ll wash the dishes. Would you mind (dry) ………….them? That would help me a lot. B: I’d be happy to. 6. A: I’m feeling kind of tired and worn out. This heavy work in the hot sun is hard on me. Do you mind (finish) ………….the work yourself? B: No problem, Grandpa. Why don’t you go in and rest? I’ll finish it up. 7. A: Would you mind if I (use) ………….your name as a reference on this job application? B: Not at all. In fact, ask them to call me. 8. A: Would you mind (wait) ………….here for just a minute? I need to run back to the classroom. I forgot my notebook. B: Sure. Go ahead. I’ll wait right here. 9. A: I need to look up the meaning of the word “stationery”. Do you mind if I (borrow) ………….your dictionary? B: No, I don’t mind. I’m not using it right now. 10. A: Since this is the first time you’ve owned a computer, would you mind If I (give) ………….you some advice? B: Not at all. I’ll appreciate it.