câu 1: cho tứ diện lồi ABCD biết ∠ABC= ∠ADC=90 độ, ∠BAD=150 độ và BD=2a. tính AC câu 2. cho lăng trụ ABC.A'B'C' đáy ABC là tam giác vuông cân tại A. biết B'B=B'A=B'C=2a, AB=a. tính chiều cao của lăng trụ.

Cho so FE+2HCL----->FEO2+H2 cho bt 11,2g FE tac dung voi dung dich HCL a) Tinh kl FECL2 tao thanh b) Tinh the tich H2 tao thanh o dktc Lam giup em voi cam on truoc ne.

( PRESENT PERFECT <=> SIMPLEPAST ) 1. how long has Michelle known you? -> how long ago__________________________ 2. how long has your family lived in HCM City? -> when_________________________________ 3. how long is it since you last saw Tom? -> how long____________________________ 4. when did your son start to listen to pop music? -> how long is it_____________________ 5. how long is it since you began swimming in the pool? -> how long ago_________________________________ 6. this is the first time we have been on a ship. -> we have not____________________________ 7. it is the first time i have read this book. -> i haven't_______________________________ ( SO/SUCH/TOO/ENOUGH) 1. the water is so dirty that we can't swim in this river. -> the water is not__________________________ 2. the game is too difficult for the the children to play. -> the game is not____________________________ ( REPORTED SPEECH) 1. he said to us: " you are my best friends" ->________________________________ 2 " we are waiting for the school bus", said the children ->____________________________________________ 3 " most of us have difficulty in learning English", said the children. ->_____________________________________________________ 4. Charlie said to Helen:" i haven't seen Kate recently" ->_____________________________________

1. No one in my class speaks English as fluently as Huong . =>Huong speaks __________________ 2. Both Lan and Huong don't like apples. => Neither Lan ____________________ 3. It was not necessary for you to work too late. => You needn't _____________________ 4.These test are too difficult for her to do . => They are such __________________ 5."We are spending more on education than ever before." He claimed => He claimed that more __________ 6. Mary last saw her parents when she left the city. => Mary was not ___________________ => The last time ____________________ 7. She last watched a film last Friday. => She has not __________________ => The last time _________________ 8. She has not met her father for two years. => It's two years ___________________ => The last time ____________________ 9."Don't forget to call on me when you are free" => She reminded __________________

word form: 1. she is so busy with..............activities that she has no time for entertainment (society) 2. the increase in population has led to................in many cities (crowd) 3. I found your performance last night.................interesting (surprise) 4. If you have a burn, quickly put the......................part under a running a cold tap (affect)

verd form: 1. Lan bought a new English book yesterday. She (read) it tonight 2. A man (cary) a large parcel got out of the car 3. Minh (take) to the dentist many times 4. the thief (catch) when he (leave) the bank 5. Hoang (know) a little english, so he wishs he (can) speak it fluently 6. To avoid (recognize) , the movie star wore dark glasses when he (go) out

Một trường tiểu học có tất cả 595 học sinh , trong đó số học sinh nữ bằng 8/9 số hs nam . Tính số hs nam và hs nữ của trường đó

cho tam giác ABC uông tại A , phân giác của góc B cắt AC tại D . Kẻ DH vuông góc với BC tại H . a) Chứng minh tam giác ABD = tam giác HBD , ,b) chứng minh BD là đườn trung trực của AH c) Gọi E là giao điểm của DH và BA . Chứng minh BD vuông góc với CE ; Tam giác BCE là tam giác gì

nêu đặc điểm sinh sản của chim và ếch

Mọi ngừi giúp mình câu 8-9 vs ạ, cảm ơn