Axit axetic không tác dụng được với chất nào sau đây?

A. Na                     

B. NaOH               

C. Cu(OH)₂.           

D. CO₂

Một đoạn mạch điện gồm một cuộn dây thuần cảm có độ tự cảm L mắc nối tiếp với là các hằng số dương và không đổi . Điều chỉnh R để biến trở nhận hai giá trị R₁ và R₂ mà với hai giá trị đó thì điện áp giữa hai đầu đoạn mạch lệch pha so với cường độ dòng điện trong mạch với các góc tương ứng là α và β thỏa mãn α + β = π 2 . Hệ thức nào sau đây đúng

A. ω L = R 1 R 2  

B. ω L = R 1 + R 2

C.  ω L = 1 2 ( R 1 + R 2 )

D.  2 ω L = R 1 + R 2

1.There are....many....trees behind my house.

2.Lan has a.....lot...of friends in Hạ Long City but she doesn't have...any..........friends in Hà Nội.

3.are There any..........eraser on the table?

-No.There is only......a..ruler and....some....pens

4.Are there......any....flowers in your shool's garden?

5.My new school has....lots.....of classrooms.

6.How.........many....stores are there on your street?

-There are a.........lot...

1.They are talking ( talk) to their teacher.

2.there are thirty-six classes(class) in out school.

3. He doesn't have many.........in Ha Noi

1, Mr Dang lives more happily than Mr Dung

=> Mr. Dung lives little happily than mr dang

2, You have more money than I do

=> I do not have more money than you.

3. They eat more fat than we do

=> We do not eat more fat than they.

4, Tim drivers more carefully than she does

=> She doesn't driver more carefully tim.

5, I study English harder than John

=> John doesn't study english harder than me

6,The Ma river is longer than the Chau river

=> The Chau river is shorter than the ma river.

7,No one in my village give me as much money as Mr. Mathew

=> Mr Mathew gives the most money in my village.

8, I think Mr. Brown is the oldest man in my country

=> I think no man is older than mr.brown

1. Her house is smaller than my house

= My house is bigger than her house.

2. Do you have a cheaper computer than this?

= Is this the cheapest computer?

3. My father has fewer days off than Lan's father?

= Lan's father has more days off than my father.

4. My father is a more careful driver than I am

= My father drives carefully.

5. Her brother drives faster than her father

= Her father drives slower than her brother.

1, I've never met anymore dependable person than George

=> George is the most dependable person george.

2. There isn't any body as kind- hearted as your mother

=> Your mother is the most kind -hearted person

3. Have you got any biger than that one?

Is this. the biggest one you have ever got?