giúp mình bài 4 và bài 5 với mình là học sinh trung bình nên hơi khó

Em có nhận xét gì về quá trình thành lập và mở rộng của nước Cham -pa

Thực hiện phản ứng este hóa 23 gam C2 H5 OH với CH3 COOH dư, với hiệu suất phản ứng đạt 55%. Khối lượng CH3 COOC2 H5 tạo thành là A: 19,8 gam. B: 44 gam. C: 12,65 gam. D: 24,2 gam.

Em hãy giải thích rõ diễn biến tâm trạng của người anh khi đứng trước bức tranh của em gái:ngỡ ngàng ,hãnh diện,xấu hổ

làm giúp mik với mik cảm ơn !!!!!!!!!!!

Mn ơi giúp mik với ạ mik đang cần gấp

Hợp chất là những chất được tạo nên từ bao nhiêu nguyên tố hóa học? A. Chỉ có 1 nguyên tố B.Chỉ từ 2 nguyên tố C.Chỉ từ 3 nguyên tố D.Từ 2 nguyên tố trở lên

Làm giúp mik câu 9 trở xuống với ạ

Ai làm giúp mình bài 2 với .....

Exercise 4: Rewrite these sentences: 1. Hurry up or we will be late for the last bus.  If 2. It was very cold yesterday, so we couldn’t go swimming.  If 3. He had a flu because he went out in the rain last night.  If 4. Ellen didn’t have much money in the bank, so she was very worried.  If 5. Stop talking or you won’t understand the lesson.  Unless 6. She can’t buy the dictionary because she doesn’t have enough money.  If Exercise 5: Choose the best answer: 1. If Jake ------------- to go on the trip, would you have gone? A. doesn’t agree B. didn’t agree C. hadn’t agreed D. wouldn’t agree 2. If energy ------------- inexpensive and unlimited, many things in the world would be different. A. is B. will be C. would be D. were 3. Unless you ------------- all of my questions, I can’t do anything to help you. A. answered B. answer C. would answer D. are answering 4. Had you told me that this was going to happen, I ------------- it. A. hadn’t believed B. don’t believe C. can’t believe D. would never have believed 5. -------------- interested in that subject, I would try to learn more about it. A. If I am B. Should I C. I was D. Were I 6. If I had enough money, --------------. A. I will buy that house B. I am buy that house C. I can buy that house D. I could buy that house 7. Had I had time, I -------------- to the beach with you this weekend. A. will come B. would come C. will have come D. would have come 8. If he -------------- that she was in the hospital, he -------------- to see her. A. knows/ will come B. knew/ would come C. had known/ would have come D. has known/will have come 9. If everything is all right, we -------------- our work on time. A. complete B. are completing C. have completed D. will complete 10. If I were you, I would work hard. A. You would rather not work so hard B. You should work harder C. You should work with me. D. Do not work so hard. 11. We didn’t visit the museum because we had no time. A. If we have time, we will visit the museum. C. If we had had time, we would have visited the museum. B. If we had time, we would visit the museum. D. If we had had time, we will have visited the museum. 12. -------------- I have time, I will go with you. A. If B. Unless C. So D. So that 13. -------------- harder, you would have passed the exam. A. If you studied B. If had you studied C. Had you studied D. Were you studied 14. If the police hadn’t saved me, I -------------- at that time. A. will die B. would die C. will have died D. would have died 15. -------------- at 4 o’clock, we would have missed seeing Bob. A. If we had gone B. Had we gone C. because we had gone D. A and B