Hai vòi cùng chảy vào bể nước ,khi bể không có nước . Nếu mở một mình vòi 1 thì sau 2 giờ đầy bể . Nếu mở một mình vòi 2 thì sau 3 giờ đầy bể . Hỏi nếu cùng một lúc mở cả hai vòi thì sau bao lâu bể đầy ?

Một con ngựa kéo một cáu xe với một lực ko đổi bằng 70N và đi được 5000m trong 1400giây tính a công của con ngựa đã thực hiện b công xuất trung bình của con ngựa

Viết lại câu 1. I saw Tom last on his wedding day. 2. I last ate raw fish when I was in Japan. 3. It's years since Mary last spoke French.

0,1728 m3 = .......... dm3 = .............lít

Rút gọn căn bậc hai theo hằng đẳng thức nha.Giúl mk với các bn ơi

Em hãy kể những triệu chứng mụn trứng cá mùa hè (Acne aestivalis)

I. Choose the best option (from A, B, C or D) to complete each sentence: (3.0pts) 1. I don't know how ____________ a birthday cake? A. make B. making C. to make D. made 2. ____________ you post this letter for me, please? – OK. A. Do B. Are C. Will D. Shall 3. The man ____________ in the garden is my grandfather. A. works B. working C. worked D. is working 4. Glass should be collected and sent to factories for ____________. A. reusing B. reducing C. refilling D. recycling 5. We ____________ morning exercise at six o’clock yesterday. A. took B. take C. are taking D. were taking 6. My friend, Lam ____________ to school late. A. is always going B. was always going C. goes always D. always goes 7. The Statue of Liberty ____________by French people. A. design B. designed C. was designed D. was designing 8. Ha Long Bay is ____________ by UNESCO as a World Heritage Site. A. studied B. recognized C. known D. seen 9. ____________ is often called “The Windy City”. A. Hawaii B. Chicago C. New York D. San Francisco 10. She promises she ____________ study hard for the next exam. A. won’t B. will C. is D. must 11. ____________ in Cambodia should be really known as a wonder. A. Angkor Wat B. The Taj Mahal C. The Hanging of Babylon D. The Statue of Zeus 12. My school hasn’t held a/an ____________ contest yet. A. flower-arranging B. flowers-arranging C. arranging-flowers D. arranging-flower II. Choose the word or phrase that is not correct in standard English. (1pt) 1. I always keep the window open so as to letting the fresh air in. A B C D 2. Lan tidied the bedrooms and cleaned the windows since yesterday. A B C D 3. He is going to get to work earlier in order impress the boss. A B C D 4. Da Lat is known like a city of pines, waterfalls and flowers. A B C D III. Complete the passage with the words given. (2pts) walk narrow friendly town We are having a wonderful time in Hoi An. The streets here are so (1) ____________ that cars are not allowed to enter the center of the (2) ____________. Therefore, we have to (3) ____________. The houses are very old but beautiful. The people are very (4) ____________ and helpful. I love this place so much. III. Put the verbs in brackets into the correct form. (2pts) 1. While Tim (drive)______________ to work, he had a wonderful idea. 2. We ( not meet) ______________ since last year. 3. Would you mind if I (turn) ______________ on the TV? 4. I (do) ______________ my homework between 8 and 9 pm last night. IV. Reorder the words to make complete sentences: (1pt) 1. always / she / watching / is / TV / . ................................................................................................. 2. have / I / already / done / my / homework / . ................................................................................................. V. Rewrite the sentences so that they have the same meaning as the original ones. (1pt) 1. We will invite some old teachers to our class meeting. " Some old teachers ______________________________________________________ 2. “I can do this test”, he said. " He said _______________________________________________________________

Tính tuổi hai anh em biết 62,5% tuổi anh hơn 75% tuổi e là 2 tuổi và 50% tuổi anh hơn 37,5% tuổi là 7 tuổi.

Giúp mik vs m.n ơi Nhanh nha mik đang cần ạ

II. Rewrite the sentences in such suggested way that the new ones still keep the same meaning as the old ones. 1. You forgot to turn off the T.V this morning, didn’t you? 2. The hot weather is so depressing. 3. A group of foreigners visited the slums last week, didn’t they?  4. That woman is very rich, but she is so modest.  5. Is pollution the most serious problem?  6. We will use renewable energy in the future  7. Does overpopulation cause a lot of social problems in this area?  8. My uncle lived in the country when he was a child. 