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dangnga2101
2 năm trước
Nguyên tử nguyên tố M có số notron nhìu hơn số proton là 1 hạt, nguyên tử nguyên tố Y có số notron bằng số proton. Trong phân tử MxY có tổng số proton là 30 hạt và M chiếm 74,19% khối lượng. Tìm tên nguyên tố M, Y và CT MxY.
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1. In 1823, the patron saint of children, Saint Nicholas appeared in a poem _________________ A Visit From Saint Nicholas. a) to call b) call c) calling d) called 2. Viet Nam is one of the _________________countries in South East Asia. a) rice – to export b) rice – exporting c) rice – exported d) rice – export 3. The Christmas songs were stories put __________________ music and most people enjoyed them. a) for b) in c) to d) on 4. The machine can help us _________________ the rice from the husk. a) to separate b) separated c) separating d) has separated 5. Santa Claus is ____________________ on the description of Saint Nicholas. a) given b) based c) received d) sent 6. The contestants made a fire by _________________ pieces of bamboo together. a) throwing b) beating c) rubbing d) breaking 7. They usually send Christmas ___________________ to their friends and relatives at Christmas. a) carols b) cards c) lighter d) trees 8. About 180 years ago, Christmas Carols became ___________________ again. a) popular b) important c) excited d) beautiful 9. The character in the poem was a fat _________________ man who wore a red suit. a) interested b) jolly c) joy d) wonderfully 10. The winners are the first ____________________ to make a fire. a) men b) some c) women d) ones 11. In this contest, participants tried to arrange flowers as _______________ as they could. a) attractively b) attract c) attractive d) attraction 12. All the ________________ in the meeting had an opportunity to speak. a) participating b) participation c) participant d) participants 13. The judges try the finished _______________ and the most delicious rice is the winner. a) produce b) productive c) products d) production 14. Each runner must take a bottle and return to the ___________________ position. a) started b) starting c) start d) starters 15. around / is / an important festival / the world / . / in / Christmas / many countries a) An important festival around the world is Christmas in many countries. b) Christmas is an important festival in many countries around the world. c) In many countries an important festival around the world is Christmas. d) Around the world in many countries is Christmas, an important festival. 16. from / to / each team / One person / the river/ . / has to run a) One person each team has to run from to the river. b) One person has to run to the river from each team. c) One person from each team has to run to the river. d) One person has to run to the river from each team. 17. No one has ever asked me that question before. a) I have never been asked that question by no one before. b) I have been asking that question before. c) I have never been asked that question before. d) I have ever been asked that question before. 18. My friend Lam is the competitor who has to fetch water. a) My friend Lam is a competitor fetched water. b) My friend Lam is the competitor who have to fetch water. c) My friend Lam is the fetching water competitor. d) My friend Lam is a water-fetching competitor. 19. “Are you leaving for Hue tomorrow?” She said to him. a) She asked him if he was leaving for Hue tomorrow. b) She asked him leaving for Hue the following day. c) She asked him to leave for Hue tomorrow. d) She asked him whether he was leaving for Hue the following day. 20. Viet Nam is a country which exports a lot of rice. a) Viet Nam is a country exports a lot of rice. b) Viet Nam is an exports rice country. c) Viet Nam is a country exported a lot of rice. d) Viet Nam is a rice – exporting country.

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