Giúp mình với câu h bỏ ,giải thích luôn cách làm với ạ

Bài1. Con kiến A tha một hạt đường, chuyển động thẳng đều về tổ O với vận tốc v= 0,5 cm/s. Khi A còn cách tổ đoạn l=1,2 m, con kiến B khởi hành tư tổ O chuyển động thẳng đều đến gặp A với vận tốc v1=2 cm/s. Khi vừa gặp A, B lập tức quay về tổ với vận tốc v2= 1cm/s. Cứ như thế, B liên tục chuyển động từ O đến gặp A rồi quay về O với các vận tốc tương ứng là 2 cm/s và 1 cm/s cho đến khi A về đến O. Gọi tổng thời gian B đi từ O đến gặp A là t1, tổng thời gian B đi từ vị trí gặp A về O là t2. a) Tính tỉ số t2/t1 b) Tính chiều dài quãng đường tổng cộng mà B đã đi được

vẽ chân dung BinZ của rap việt, vẽ trên giấy A4, vẽ ít nhất là nửa người, không vẽ mỗi cái mặt, không vẽ qua loa

tìm tập xác định của hàm số y=2x+1/x^3-x-2

1.Cho CrA = [ -4;√7 ) , CrA = ( -6;2 ) hợp ( √3; √13 ).Tìm A,B và Cr ( A giao B ) 2.Cho A = [ m -1;m + 1/ 2 ] ; B = ( âm vô cùng ; -1 ) hợp [ 3; dương vô cùng )

Bài 4: (3,5 điểm) Cho hình bình hành ABCD (AB > BC) có M, N lần lượt là trung điểm của AB và CD. a) Chứng minh: AMCN là hình bình hành b) Chứng minh: AC, BD, MN đồng quy c) Gọi E là giao của AD và MC. Chứng minh: AM là đường trung bình của ΔECD

tìm giá trị lớn nhất của các biểu thức sau biểu thức A = 12a - 4a mũ 2 +3

tìm trường từ vựng trong Tôi đi học

15-MINUTE TEST. (UNIT 1)1-5. Choose the word whose underlined part is pronounced differently from that of the other words. 1. A. charity B. chin C. chip D. chaos 2. A. choice B. chapter C. challenge D. character 3. A. stomachB. matchC. switchD. catch 4. A. chip B. child C. chemist D. French 5. A. genius B. general C. gentle D. gaze 6-15. Choose the best answer A, B, C or D to complete each sentence. 6. People say that there must be _____ trust between true friends. A. common B. shared C. social D. mutual 7. We always admire the _____ between the two scientists. A. difference B. harmony C. contribution D. friendship 8. His father's death was a great _____ to him. A. sorrow B. happiness C. pursuit D. demand 9. At work,she has many business _____ but very few true friends. A. customers B. relatives C. acquaintances D. friends 10. If you only care about your interests and feelings, you are very _____. A. happy B. loyal C. friendly D. selfish 11. She isin a hurry. She has a train _____. A. catch B. to catch C. catching D. caught 12. This dress makes me _____ fat. A. look B. looking C. to look D. looked 13. The children cheered wildly when the teacher let them _____ a game. A. playB. to play C. playing D. played 14. Don't let her _____ your children. A. upset B. to upset C. upsetting D. to upsetting 15. It was too difficult for the police ______ the truth within 2 days. A. to find B. finding C. finding out D. to find out16-20. Choose the underlined part among A, B, C or D that needs correcting. 16. Where (A) mutual(B) sympathydoes not (C) exist, friendship is (D) impossibility. 17. Everyone (A) hasa (B) number(C) ofacquaintances, but (D) allhave many true friends. 18. (A) Somepeople (B) areincapable (C) in(D) findinggood friends. 19. It is comfortable (A) to workwith (B) suchan (C) understoodperson (D) likehim. 20. I (A) made friend(B) withLan (C) whenshe was on her trip (D) toDo Son. 21-25. Choose the word or phrase among A, B, C or D that best fits the blank space in the following passage. Dear Mary,How are things with you? Since I saw you last week, I've been very ill. By the time I arrived home after seeing you on Monday, I had an awful headache. I thought that perhaps my eyes were tired (21) _____ . I’d been working so hard, so I took some aspirins and went to bed. However, when I woke up the next morning, the headache was worse than ever, and my throat was sore. I triedto get up but my arm and leg (22) _____ stiff. I saw the doctor and she told me I had a temperature. She said I probably had flu. She advised me to take some medicine and (23) _____ in bed. The medicine tasted horrible and it didn't make me feel any better. I felt sick and I didn't want to eat anything at all although I was very (24) _____ . I have almost recovered now, and I'm going to start work again tomorrow. I still have a slight cold and a cough but my chest doesn't hurt when I (25) _____. Can we meet on Saturday? I'm looking forward to seeing you. 21. A. though B. as C. while D. during 22. A. looked B. moved C. felt D. sensed 23. A. staying B. stayed C. stay D. stays 24. A. ill B. heavy C. hungry D. thirsty 25. A. breathe B. ache C. cure D. bleed 26-30. Choose the correct sentence among A, B, C or D which has the same meaning as the given one. 26. My teacher wouldn't let me leave early. A. My teacher refused to let me leave early. B. My teacher refused letting me leave early. C. My teacher allowed me to leave early. D. My teacher permitted me to leave early. 27. I've warned you not to leave the door unlocked. A. You shouldn't unlock the door. B. Leaving the door unlocked was not good. C. I'vewarned you about leaving the door unlocked. D. I told you not to lock the door. 28. It isn't necessary for you to finish the work right now. A. It is necessary for you to start the work right now. B. It isn't unnecessary for you to finish the work right now. C. You don't have to finish the work right now. D. You mustn't finish the work right now 29. The garden is too small to play football in. A. The garden is so small not to play football in. B. The garden is small enough to play football in. C. The garden isn't big enough to play football in. D. The garden is such small that they can't play football in. 30. After fighting the fire for an hour, the fire brigade succeeded in putting it out. A. The fire brigade managed to put the fire out after fighting it for an hour. B. The fire brigade couldn't put the fire out after fighting it for an hour. C The fire brigade puts the fire out after fighting it for an hour. D. The fire brigade, was unable to put the fire out after fighting it for an hour

1. Lấy một câu văn đặt tên cho vấn đề gợi ra từ bức ảnh trên. 2. Viết một bài văn ngắn với tựa đề "Nhân danh lòng tốt" để bày tỏ suy nghĩ của anh chị về vấn đề gợi ra từ bức ảnh trên.