Cặp chất nào sau đây là đồng phân của nhau? A. Etan và etilen. B. Butađien và but-1-in. C. Pentan và isobutan. D. Propin và propilen. Mng giúp em vs ạ giải thích giúp em

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REVISION I. Complete the sentences using the past simple form of the verbs. ( CHIA ĐỘNG TỪ TRONG NGOẶC DÙNG THÌ QUÁ KHỨ ĐƠN ) 1- I (be).......................................a student 2 years ago. 2- He (be).................................. a doctor two years ago. 3- They (be)................................. farmers last year. 4- Lan and Ba (be) .........................nurses last year. 5- It (be not)............................ cold yesterday. 6- She (be not)........................a pupil last week. 7- This hat (be not) .........................new yesterday. 8- My parents (be not) .......................teachers two years ago. 9- He (be not) ..........................a mechanic last Monday. 10- (Be)................... he an engineer yesterday. No , he (be not)..................... II.Complete the sentences using the past simple form of the verbs. 1. I _____ at home all weekend. ( stay) 2. Angela ______ to the cinema last night. (go) 3. My friends ______ a great time in Nha Trang last year. (have) 4. My vacation in Hue ______ wonderful. (be) 5. Last summer I _____ Ngoc Son Temple in Ha Noi. (visit) 6. My parents ____ very tired after the trip. ( be) 7. I _______ a lot of gifts for my little sister. (buy) 8. Lan and Mai ______ sharks, dolphins and turtles at Tri Nguyen aquarium.(see) 9. Trung _____ chicken and rice for dinner. (eat) 10. They ____ about their holiday in Hoi An. (talk) 11. Phuong _____ to Hanoi yesterday. (return) 12. We _____ the food was delicious.(think) 13. Yesterday, I (go)______ to the restaurant with a client. 14. We (drive) ______ around the parking lot for 20 mins to find a parking space. 15. When we (arrive) ______ at the restaurant, the place (be) ______ full. 16. The waitress (ask) ______ us if we (have) reservations. 17. I (say), "No, my secretary forgets to make them." 18. The waitress (tell)______ us to come back in two hours. 19. My client and I slowly (walk) ______ back to the car. 20. Then we (see) ______ a small grocery store.