Hòa tan m (g) hỗn hợp X gồm Al và Na có tỉ lệ mol 1:2 vào nước dư thu được 4,48 (l) khí (đktc). Gíá trị của m là:

A. 7,3

B. 5,84

C. 6,15

D. 3,65

1.Our teachers have explained the English grammar.

\(\Rightarrow\) The English grammar has been explained by our teachers.

2.Some drunk drivers caused the accident in this city.

\(\Rightarrow\) The accidents in this city were caused by some drunk drivers.

3.Tom will visit his parents next month.

\(\Rightarrow\) His parents will be visited next month by Tom.

4.The manager didn’t phone the secretary this morning.

\(\Rightarrow\) The secretary wasn't phoned this morning by the manager.

5.Did Mary this beautiful dress?

\(\Rightarrow\) Was this beautiful dress bought by Mary?

1.I won’t hang these old pictures in the living room.

\(\Rightarrow\) These old pictures won't be hung in the living room.

2.The German didn’t build this factory during the Second World War.

\(\Rightarrow\) This factory wasn't built during the Second World Wả by the German.

3.The Greens are going to paint this house and these cars for Christmas Day.

\(\Rightarrow\)This house an these cars are going to be painted for Christmas Day by the Greens.

4.Ann had fed the cats before she went to the cinema.

\(\Rightarrow\)The cats had been fed before she went to the cinema by Ann.

5.The students have discussed the pollution problems since last week.

\(\Rightarrow\) The pollution problems have been discussed since last week by the students.

mk bỏ lâu rồi! Lâu lắm rồi không chơi

Tổng vận tốc thuyền máy và dòng nước là :

22,6 + 2,2 = 24,8 (km/giờ)

Đổi 1 giờ 15 phút = 1,25 giờ

Quãng sông AB dài là :

24,8 x 1,25 = 31 (km)

ĐS : 31km

a, she (play) is playing chess with her friend at the moment. She often (play) plays chess when she (have) has free time.

b, Does she (do) do aerobics every morning?

c, how often does Hoa (go) go to see a movie?

d, Mary (have) will have her summer vacation next month. 

e, we (not like) don't like to play video games.

f, let's (listen) listen to some music on the radio.

1. Everybody (wait) is waiting for the president in the hall now.

2. Where is your mother?

- She(be) is in the sitting- room. She (read) is reading newspaper.

3. Look! That plane (fly) is flying toward the airport. It (land) is landing

4.We (see) will see the movie tomorrow. Will You (join) join ?

5. He is busy at the moment. But he (come) is coming to give you a helping hand as soon as he finishes his work.

6. Long(fall) fell down the stairs this morning and (break) broke his leg.

1. Hoa is the most beautiful girl in her class. (beauty)

2. Hanoi people were friendly (friend)

3. He is a famous actor (act)

4. This is the biggest building in the city (build)

5. Bill Gates is a famous busier (busy)

6. Hoa has a fine collection of stamp. (collect)

7. Minh looks worried again. What's the matter with him? (worry)

8. He lives in mountainous area with his parents. (mountain )

9. You should be careful when driving (care)