1. It started to snow at 5 o'clock. 
=> It has snowed since 5 o'clock. 
2. When did you go to bed last night? 
=> What time did you go to bed last night? 
3.     This house is less comfortable than the one we saw last month.

==> This house is not as comfortable as the one we saw last month.

4.     Sue began to be interested in healthy eating 3 years ago.

==> Sue has been interested in healthy eating for 3 years

5.     What time does Paul have to leave ?

==> Do you know what time Paul has to leave?

6.     This book is very boring, and so is that one.

==> This book is as boring as that one

7. Will it be necessary for me to sleep under a net? 
=> Shall I have to sleep under a net? 

8.  I last read a book on September 20th. 
=> I haven't read a book since September 20th. 

 ptpứ : FexOy + 2yHCl --> xFeCl2y/x + yH2O 
mddHCl = 52,14x1,05 = 54,75(g) 
nHCl = 54,75x10%/36,5 = 0,15(mol) 
=>nFexOy = 0,15/2y(mol) 
=>mFexOy = 4g 
nên MFexOy = 4x2y/0,15 =160y/3 
maMFexOy = 56x+16y 
=>56x+16y = 160y/3 
Giải pt trên ta dc x=2,y=3.Vậy công thức của oxit sắt là Fe2O3

Vận tốc của chất điểm dao động điều hòa có giá trị cực tiểu khi li độ bằng không

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Bạn đặt câu hỏi một đằng mà câu trả lời một nẻo

HI! I come from a family of five people: my parents, my two younger brothers and I. 
My parents are farmers who work very hard in the field. On the trip, they are so busy. Inspite of its, they always take more time as possible to take care of us. My father is great father. Dad always teachs me things to do and not to do in this life. He is also good husband for may mom. On the trip, he often helps my mom to cook some special dishes. And at weekend, he usually fixes everything broken in our house. 
About my mother, she is a caring woman. mom is always the first person to get up early in the morning to wake up I and my first younger brother and prepare breakfast before going to school. She is very thoughful! About my two younger brothers. the first one is 16 years old and the second one is 6 years old. they are obedient! And I, I'm in final hingh school and in my attempt. I'm under a lot of study pressure. inspite of its, I always dream and try to study harder and harder to get success in the future. 
It's my family. I feel very happy in it. And I love my family more than anything! 

She/takes part in/school all the plays theater group/./often/of the/ plays

==> She often takes part in plays of the school all the plays theater group