Tính : `1/(1.2) + 1/(2.3) + ... + 1/(49.50)`

Một ô tô đi từ A đến B với vận tốc 25km/h, lúc về người đó đi với vận tốc 30km/h nên thời gian đi và về là 3h40 phút. Tính quãng đường AB?

Ai giúp em vs ạ em cảm ơn trước

Question 1: Choose the best option( A, B, C or D) to complete the sentences: 1. My mum …………..the bus to work every morning. A. takes B. goes C. does D. runs 2. Before the new system of traffic control, there……….be more accidents. A. use to B. used to C. is used to D. was used to 3. Traffic accidents can be prevented if people……….the rules. A. remember B. obey C. go after D. take care of 4. In spite of having a happy……….., the film begins with a terrible disaster. A. ending B. acting C. opening D. setting 5. On each Thanksgiving, families and friends…………….to have a feast. A. met B. arrive C. appear D. gather 6. The end of the film was so…… A. moved B. moving C. move D. movable 7. Everybody attends the festival just……………fun. A. with B. for C. in D. of Question 2: Choose the best option( A, B, C or D) to complete the text below Tet or Lunar New Year holiday is the most important ………….(9) for Vietnamese people. Tet is a festival which …………(10) in late January or early February. Before Tet, people usually clean and …………..(11) their homes. They go to market to ……….(12) candy, jams or dried water melon seeds. They also get new clothes which are traditional at Tet. They often buy peach blossoms and marigolds which are ……….(13) flowers at Tet holiday. Tet is a time ……..(14) family members gather and have some special meals………… (15) special food such as sticky rice cakes. People often …………..(16) relatives and close friends on the second day of the holiday. 9. A. festival B. celebration C. occasion D. A& B are correct 10. A. happen B. take place C. occurs D. All are correct 11. A. decorating B. decorate C. to decorate D. decorated 12. A. make B. take C. buy D. sell 13. A. tradition B. traditional C. traditionally D. traditions 14. A. with B. in C. to D. for 15. A. for B. with C. to D. of 16. A. visit B. love C. hate D. leave

Mary took some photographs last year , and they are being shown in an exhibition some photographs .....................................................................................................

Giúp mình với ạ chỉ câu b thôi. Cảm ơn m.n nhìuuu!

Ai giúp mình tiếng anh với ạ mình cảm ơn

Viết chữ calligraphy Bánh Cua Ko kí hoặc kí xa thật xa

a) p = 1 + 9/45 + 9/105 + 9/189 + ... + 9/29997

Có những chất: Na2O, Na, NaOH, Na2SO4, Na2CO3, NaCl. a) Dựa vào mối quan hệ giữa các chất, hãy sắp xếp các chất trên thành một dãy chuyển đổi hóa học. b) Viết các phương trình hóa học cho dãy chuyển đổi hóa học ở câu a.