.Một xe đạp khởi hành từ điểm A,chạy với vận tốc 20km/h. Sau đó 3 giờ, một xe hơi cũng khởi hành từ điểm A, đuổi theo xe đạp với vận tốc 50km/h. Hỏi xe hơi chạy trong bao lâu thì đuổi kịp xe đạp?

Năm nay tuổi bố Việt hơn Việt 28 tuổi . Cách đây 6 năm tuổi bố gấp 9/2 lần tuổi Việt . Hỏi năm nay Việt vừ bố bao nhiêu tuổi

giúp mình ạ sắp tới giờ học rồi huhu hứa vote 5 sao

Tính hoá trị của các nguyên tố và nhóm nguyên tử trong các hợp chất sau: a,NH3 b,H2SO4 c,Na2CO3 d,Fe2O3 - N có hoá trị là: - SO4 có hoá trị là: - Na có hoá trị là: - Fe có hoá trị là:

Giúp e giải 2 câu này với ạ? E cần gấp ạ :(

12. John ............a book when I saw him. A. is reading B. read C. was reading D. reading 13. He said he............return later. A. will B. would C. can D. would be 14. Jack.............the door. A. has just opened B. open C. will have opened D. opening 15. I have been waiting for you............... A. since early morning B. since 9 a.m C. for two hours D. all are correct 16. My sister............for you since yesterday. A. is looking B. was looking C. has been looking D. looked 17. Jack............the door. A. has just painted B. paint C. will have painted D. painting 18. The train............half an hour. A. has been leaving B. left C. has lelt D. had lelt 19. We............Doris since last Sunday. A. don't see B. haven't seen C. didn't see D. hadn't seen 20. When I last saw him, he............in London. A. has lived B. is living C. was living D. has been living 21. After I...............lunch, I looked for my bag. A. had B. had had C. have has D. have had 22. By the end of next year, Geoge...............English for 2 years. A. will have learned B. will learn C. has learned D. would learn 23. The man got out the car,...............round to the back and opened the boot. A. walking B. walked C. walks D. walk 24. For several years his ambition...............to be a pilot. A. is B. has been C. was D. had been 25. Henry............into the restaurant when the writer was having dinner. A. was going B. went C. has gone D. did go

Các ace tốt bụng và học giỏi hãy giúp em đi ạ ! Em cảm ơn nhiều !!

1.Reduce means not buying products which are ____________.(package)2.She is one of____________from Friends of the Earth.(represent)3.Melt the____________until it becomes the liquid.( mix)4.The bottles can be ____________several times.(use)5.Viet Nam is very rich in ____________resources.(nature)6.Compost is a wonderful natural____________.(fertilize)7.Share your ____________story with our readers! (recycle)8.Dry the glass pieces____________.( complete)9.The children enjoy playing____________toys.(wood)10.We make vegetable matter into compost and ____________our field. ( fertilizer)

Câu 1: 2/21+9/-36 câu 2: -12/18+ -21/35 câu3: -3/21+ 6/42 câu4: -18/24+15/-21 . Ai làm được mình cho 5sao

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