mình cần gấp mình hứa sẽ đánh giá 5 sao Tổng số hạt cơ bản trong nguyên tử nhôm là 40; trong đó, số hạt không mang điện ít hơn số hạt mang điện là 12. a. Viết kí hiệu nguyên tử nhôm. b. Nhôm còn có một đồng vị khác với số notron ít hơn đồng vị nhôm ở trên 1 đơn vị. Hãy xác định kí hiệu nguyên tử của đồng vị này.

không cần giải thích đâu ạ 1. My father can make beautiful pieces of art ________ empty eggshells. a. of b. from c. in d. into 2. Why don’t you take ________ a new hobby? a. up b. in c. over d. after 3. Collecting cars is a(n) ________ hobby. It costs a lot of money. a. interesting b. cheap c. expensive d. unusual 4. More people are ________ birds today than ever before. a. seeing b. looking c. hearing d. watching 5. Do you enjoy ________ board games? a. play b. to play c. playing d. played 6. Be careful not to drop it; it’s very ________. a. unique b. fragile c. difficult d. unusual

Ex 3 : Rewrite sentences We started living here fifteen years ago. --> We have ……………………………………………………………….. I have learnt English for 10 years now. ( I began …………………………..…………………………………………… She moved to London 20 years ago. ( She has …………………………………………………………………………… The Pikes haven’t visited Paris for 2 years. ( The last time ………………………….……………………………… The last time I saw John was when he was leaving for Edinburgh. ( I haven’t …………………………………………………………………………………………………… John’s career as a television presenter began five years ago. ( John has ……………………………………………………………………………………………………… How long have your family read Tuoi Tre Newspaper ? ( When did your ……………………………………………………………………………………………… My old friend started working on that farm in 2005. ( Since 2005, ………………………………………………………………………………………………… When did he start teaching Physical Education in this school ? ( How long …………………………………………………………………………………………………… My mother has had this washing machine for a long time. ( My mother …………………………………………………………………………………………………… My father stopped drinking champagne ten years ago. ( My father hasn’t …………………………………………………………………………………………… Jane’s grandma hasn’t planted trees in the garden for 5 months. ( Jane’s grandma stopped …………………………………………………………………………………… I have never met a more warm-hearted person than my mother is. ( My mother is ………………………………………………………………………………………………… I have never seen such a bad film as that one in the cinema. ( That is the …………………………………………………………………………………………………… 15. We haven’t seen Mary since we left the university. ( We last …………………………………………… 16. The last time we saw her was on Christmas day. --> We haven’t ..................................................... 17. I haven’t eaten this kind of food before. -->This is 18. It started raining an hour ago. --> It has 19. We haven’t visited my grandfather for two months. -->The last time 20. My brother hasn’t seen his best friend for nearly five years. -->It’s viết những cái vào phần "..........."thôi nhé!

giúp mình với trước 7h tối Một con lắc đơn gồm một vật nhỏ treo vào một điểm cố định bằng sợi dây mảnh, nhẹ, không dãn có chiều dài l = 1 m. Kéo cho dây treo làm với đường thẳng đứng một góc 45độ rồi thả nhẹ. Bỏ qua sức cảncủa không khí. Lấy g = 10 m/s2 Tốc độ của vật nhỏ khi qua vị trí dây treo lệch góc 300so với phương thẳng đứng là A. 17,8 m/s. B. 35,2 m/s. C. 1,78 m/s. D. 3,52 m/s.

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cho em hỏi thành phần chính của bột đá phấn là gì ạ

Ai giải thích và làm giúp em với ạ em hứa cho 5 sao và câu trả lời hay nhất ạ. Mark the letter A, B, C or D on your answer sheet to indicate the sentence that best fits the meaning of the given one. Question 33: Have they ever been to the Philippines? A. They have ever been to the Philippines, have they? B. They have ever been to the Philippines, don’t they? C. They have ever been to the Philippines, has they? D. They have ever been to the Philippines, haven’t they? Question 34: I'd rather you didn't smoke here. A. Would you mind not smoking here? B. Would you mind not smoke here? C. Would you mind if I didn’t smoke here? D. Would you mind not to smoking here? Question 35: It was such a cold day that we stayed indoors. A. The day was so cold for us to stay indoors. B. The day is so cold that we stayed indoors. C. The day was so cold that we stayed indoors. D. The day was so cold that we stay indoors. Question 36: Although Peter tried hard, he couldn't start his car. A. No matter hard Peter tried, he couldn't start his car B. No matter how Peter tried hard, he couldn't start his car C. No matter how hard Peter tried, he couldn't started his car D. No matter how hard Peter tried, he couldn't start his car Mark the letter A, B, C or D on your answer sheet to indicate the sentence that best fits the combination of the given sentences. Question 37: It doesn’t rain in winter. People in this area lack water. A. It doesn’t rain in winter, so people in this area lacks water. B. It doesn’t rain in winter, so people in this area lack water. C. It doesn’t rain in winter, so people in this area is lack water. D. It didn’t rain in winter, so people in this area lack water. Question 38: John woke up late. He didn’t have time for breakfast. A. John woke up too late for have time for breakfast. B. John woke up late to have time for breakfast. C. John woke up too late to have time for breakfast. D. John woke up late enough to have time for breakfast. Question 39: Neil Armstrong lived in the USA. He walked on the moon. A. Neil Armstrong, who walked on the moon, lived in the USA. B. Neil Armstrong who walked on the moon lived in the USA. C. Neil Armstrong, whom walked on the moon, lived in the USA. D. Neil Armstrong, that walked on the moon, lived in the USA. Question 40: I don’t have money. I can’t buy that house A. If I have money, I would buy that house. B. If I had money, I would buy that house. C. If I had money, I will buy that house. D. If I had had money, I would have bought that house.

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Giải giúp mình với cảm ơn nhiều

Hòa tan hết a gam kim loại Na trong dung dịch HCl. Sau phản ứng người ta thu được dung dịch A và 3,36 lít H2 (đktc). a. Tính a? b. Tính khối lượng các chất tan trong dd A biết rằng lượng axit dùng cho thí nghiệm trên phản ứng vừa đủ với 3,25 gam Zn