1. Hoi An is famous for its ancient houses (fame)

2. Water has not color. It is a uncolored liquid (color)

3. Mozart was one of the great musicians (music)

4. Life today is different from life 50 years ago (differ)

5. Michael Faraday is one of the British scientists (science)

6. This is my stamp collection (collect)

1. That exercise is not as easy as this exercise

2. It's difficult to train dogs

3. They think that it's not easy to learn English

4. The weather is so cold that we don't go out.

5. The weather isn't warm enough for us to go out.

6. The film is too boring for us to see

7. The bathroom has a sink, a tub and a shower

8. No house in the village is older than his house

9. Is this the best bike you have?

10. It takes him one hour to get to work.

11. How much does this T.V price?

John speaks Vietnamese very badly

Where are you going this summer holiday?

Gọi số học sinh đạt giải cả 3 môn là a (học sinh)
Gọi số học sinh đạt giải cả 2 môn là b (học sinh)
Gọi số học sinh chỉ đạt giải 1 môn là c (học sinh)
Tổng số giải đạt được là: 
3 x a + 2 x b + c = 15 (giải).
Vì tổng số học sinh đạt 3 giải, 2 giải, 1 giải tăng dần nên a < b < c.
Vì bất kỳ 2 môn nào cũng có ít nhất 1 học sinh đạt giải cả 2 môn nên:
- Có ít nhất 1 học sinh đạt giải cả 2 môn Văn và Toán.
- Có ít nhất 1 học sinh đạt giải cả 2 môn Toán và Ngoại Ngữ.
- Có ít nhất 1 học sinh đạt giải cả 2 môn Văn và Ngoại Ngữ.
Do vậy b= 3.
Giả sử a = 2 thì b bé nhất là 3, c bé nhất là 4; do đó tổng số giải bé nhất là:
3 x 2 + 2 x 3 + 4 = 16 > 15 (loại). Do đó a < 2, nên a = 1.
Ta có: 3 x 1 + 2 x b + c = 15 suy ra: 2 x b + c = 12.
Nếu b = 3 thì c = 12 - 2 x 3 = 6 (đúng). 
Nếu b = 4 thì c = 12 - 2 x 4 = 4 (loại vì trái với điều kiện b < c)
Vậy có 1 bạn đạt 3 giải, 3 bạn đạt 2 giải, 6 bạn đạt 1 giải.
Đội tuyển đó có số học sinh là: 
                                1 + 3 + 6 = 10 (bạn). 

                                                Đáp số: 10 bạn

1. This is the first time he went abroad.

=> He hasn't went abroad.

2. She started driving 1 month ago

=> She hasn't drived for 1 month

3. We began eating when it started to rain

=> We have eaten since it started to rain

4. I last had my hair cut when I left her.

=> I haven't cut my hair since I left her.

5. The last time she kissed me was 5 months ago

=> She hasn't kissed me for 5 months.

6. It is a long time since we last met.

=> We haven't met for a long time

7. When did you have it?

=> How long have you had it?

8. This is the first time I had such a delicious meal.

=> I haven't had such a delicious meal.

9. I haven't seen him for 8 days

=> The last day I've seen him was 8 days ago.

10. I haven't taken a bath since Monday

=> It is Monday since I took a bath.

1. You are lucky this time, aren't you?

2. I'm right to say that, aren't I?

3. She will marry an American , won't she?

4. I am your teacher , aren't I?

5. They always go to bed at ... , don't they?

6. He used to smoke agars, didn't he?

7. All can't speak at a time, aren't they?

8. Few people knew the answer, didn't they?

9. The children rarely cries, do they?

10. They did nothing, did they?

11. Open your book, will you?

12. Don't talk in class, will you?

13. Let's go to the cinema, shall you?

14. Let me lend you a hand, shall you?

We put all our books on the bookshelf.

Ta có : \(p_x+p_y+p_t+p_a+p_b+p_d=63\)

và \(p_x=p_y+1;p_y=p_t+1;p_t=p_a+1;p_a=p_b+1\)

Suy ra : \(p_d+\left(p_d+1\right)+\left(p_d+2\right)+\left(p_d+3\right)+\left(p_d+4\right)+\left(p_d+5\right)=63\)

\(\Leftrightarrow6p_d=48\Leftrightarrow p_d=8\)

Vậy ta có số hạt proton của các nguyên tử theo thứ tự tăng dần là : 8 ; 9 ; 10 ; 11 ; 12 ; 13

.......