Cho đt(o) có hai đường kính AB và CD vuông góc vs nhau. Vậy AB vuông vs CD tại O thì góc O bằng 90 độ là sai hay đúng

zẽ chibi thức khuya để chờ fanpage hoidap247 rep tin nhắn của mk NL : Có ai còn thức hem =))

giúp mik lm bài cuối vs mik đang cần gấp

Vẽ mầm ngủ/chibi ngủ/anime ngủ/... nhưng phải ngủ NL: có cách nào gửi ảnh bằng mt cây khum nhỉ??? máy tui có cam mà khum bít chụp như nào :(( Nhắc nhẹ mấy bạn : MUỘN RÒI ĐI NGỦ ĐI !!!! NGHE RÕ CHƯA =)) <3 <3 <3

Giải pt: `2\sqrt(3x+1)-\sqrt(x-1)=2\sqrt(2x-1)`

Khi nghĩ về một đời người, tôi thường nhớ về rừng cây. Khi nghĩ về một rừng cây tôi thường nhớ về nhiều người. Trẻ trung như cụm hoa hồng, hồn nhiên như ngàn ánh lửa chiều hôm khi gió về! Cây đã mọc từ thuở nào trên đồi núi thật cằn khô, Cây có hiểu vì sao, chim thường kéo về làm tổ Và em như cụm lan mọc từ những cành cổ thụ già kia! Và tôi vẫn nhớ hoài một loài cây, sống gần nhau thân mới thẳng Có một cây là có rừng, và rừng sẽ lên xanh, rừng giữ đất quê hương! Ai cũng chọn việc nhẹ nhàng, gian khổ sẽ dành phần ai? Ai cũng một thời trẻ trai, cũng từng nghĩ về đời mình Phải đâu may nhờ rủi chịu, phải đâu trong đục cũng đành. Phải không anh? Phải không em? Chân lý thuộc về mọi người, không chịu sống đời nhỏ nhoi! Xin hát về bạn bè tôi, những người sống vì mọi người. Ngày đêm canh giữ đất trời, rạng rỡ như rừng mai nở chiều xuân. (Lời bài hát “Một đời người một rừng cây” – Nhạc sĩ Trần Long Ẩn) a. Ca từ bài hát thể hiện những suy ngẫm của nhân vật “tôi” về điều gì? Qua những suy ngẫm ấy, tác giả “xin hát” lời ngợi ca dành cho những con người như thế nào? b. Những từ “rừng cây, cây, hoa hồng, lan, cổ thụ” có nét chung nào về nghĩa? c. Xét theo mục đích nói, câu “Phải không anh? Phải không em?” thuộc kiểu câu gì? Chỉ ra mục đích nói của câu này. d. Xác định và phân tích giá trị biểu đạt của 2 biện pháp tu từ nổi bật trong những câu sau: Khi nghĩ về một đời người, tôi thường nhớ về rừng cây. Khi nghĩ về một rừng cây tôi thường nhớ về nhiều người. Trẻ trung như cụm hoa hồng, hồn nhiên như ngàn ánh lửa chiều hôm khi gió về!

Hỗn hợp `X` chứa hai amin kế tiếp thuộc dãy đồng đẳng của metylamin. Hỗn hợp `Y` chứa glyxin và lysin. Đốt cháy hoàn toàn `0,1` mol hồn hợp `Z` (gồm `X` và `Y`) cần vừa đủ `0,5175` mol `O_2`, thu được `8,19` gam `H_2O`; `9,072` lít (đktc) hỗn hợp `CO_2` và `N_2`. Phần trăm khối lượng của amin có khối lượng phân tử nhỏ hơn trong `Z` là: `16,05%` ---- mik cảm ơn---

Question 40: If I got promotion at work, I’ll take everyone out to celebrate. A. got B. work C. take D. out Question 41: If I were you, I will never forgive him for his telling lies. A. were B. will C. him D. lies Question 42: If you are late at a job interview, you won’t make a good impression. A. are B. at C. won’t D. impression Question 43: Oceans willrun out of fish within the next 50 years if we won’t stop dynamite fishing. A. will B. run out of C. won’t stop D. fishing Question 44: If I am you, I would confess to my mom before she finds out the truth herself. A. am B. would confess C. finds out D. herself Question 45: If you had a headache, you should takean aspirin. A. If B. had C. take D. an Question 46:If only I weren’t on a diet, I will eat a lot of chocolate. A. If only B. on C. will D. much Question 47:Provided that you will hand in your paper before 5 p.m today, I will accept your submission. A. Provided that B. will hand C. before D. will accept Question 48: What will you do if a billionaire gave you one third of his fortune? A. will B. do C. a D. one third Question 49: He will be able to operate the machines if somebodyshown him how. A. will be B. to operate C. somebody D. shown Question 50: Suppose they cancelled the flight yesterday, how would you have got home? A. Suppose B. cancelled C. would D. got Question 51: If it hadn’t been because his support, I couldn’t have completed the mission. A. hadn’t B. because C. couldn’t D. completed Question 52:Not for two minor mistakes, I would have got full marks for the test. A. Not B. mistakes C. have got D. for Question 53: The tourists wouldn’t have been so angry if the trip hadn’t cancelled right before the departure time. A. have been B. if C. hadn’t cancelled D.before Question 54:Were the werewolf here, would you stay and protect me or ran for your life? A. Were B. stay C. protect D. ran Question 55: If I had known that the road were flooded, I would never have taken that way. A. had known B. were flooded C. would D. have taken Question 56: If I had known he is not at home, I wouldn’t have gone all the wayto his house. A. is not B. have gone C. the way D. to Question 57: Hadn’t it been for his words, I wouldn’t have gone that long as I did. A. hadn’t it been for B. wouldn’t have gone C. long D. did Question 58: They treat me as if I would be a three-year-old child. A. treat B. as if C. would be D. three-year-old Question 59: She shouted so loud as though she was on pins and needles. A. shouted B. as though C. was D. pins and needles

Cho hình thang vuông ABCD có `hat(A) =hat(D) = 90^0`, AB = AD = 2 cm; DC= 4cm. Kẻ BH ⊥ DC. Tính BH

Question 32: Were it not for you, I would never go out at midnight. A. If it were for you, I would go out at midnight. B. If it were not for you, I wouldn’t go out at midnight. C. Had it not been for you, I wouldn’t go out at midnight. D. Because of you, I wouldn’t go out at midnight. Question 33:If the players had been more focused, they would have won the game. A. Had the players been more focused, they would have won the game. B. If they won the game, the players would be more focused. C. They would win the game were the players more focused. D. Should the players focus more, they will win the game. Question 34: Although his doctor requested him to stay in bed, he got up suffering an immediate relapse.
 A. If only he had stayed in bed as the doctor requested, he would not have suffered a relapse.
 B. Although he had tried to stay in bed as requested, he suffered an immediate relapse. C. Having defied his doctor’s request to get up, he became ill again as soon as he stayed in bed. D. As he was trying to get up, he remembered that his doctor had requested him to stay in bed. Question 35: We are planning to have a picnic in the suburbs as long as the weather stays fine. A. We’re planning to have a picnic in the suburbs despite the bad weather. B. If the weather had been fine, we would have had a picnic in the suburbs. C. If the weather is fine, we will have a picnic in the suburbs. 
 D. If the suburbs are good enough, we will have a picnic there. 
 Question 36: I regret spending too much money on games. A. I wish I didn’t spend money on games. B. I hope I won’t have to spend money on games. C. If only I had not spent too much money on games. D. I regret having spent too much money on games. Question 37:If I had known your house address, I wouldn’t have sent it to your office. A. Provided that I knew your house address, I would send it to your office. B. Had I known your house address, I would have never sent it to your office. C. I would send it to your office if I knew the address. D. When I know your house address, I will send it to you Question 38:Hanoi suffers alarming air pollution because of the heavy traffic. A. But for the heavy traffic, the air in Hanoi wouldn’t be alarmingly polluted. B. Unless Hanoi is alarmingly polluted, the traffic may not be so heavy. C. Suppose Hanoi were heavily polluted, the traffic would be an alarming problem. D. If Hanoi were less polluted, the traffic would be much heavier. Question 39:If you don't stop eating candies, you will put on weight very quickly. A. Stop eating candies, or you will put on weight very quickly. B. You will put on weight very quickly though you eat candies. C. You won't put on weight very quickly if you eat candies. D. Unless you eat candies, you will put on weight very quickly.