1. eating

2. stop

3. playing

4. brushes

5. listening

6. travels

7. live

8. wash

9. works

10. writing

VII.

1. Mrs. Vien is taking the vegetables to the market.

2. How many teachers are there in your school?

3. This sign says "No Parking" so we mustn't park here.

4. We walk home and have luch at twelve o'clock.

5. Trang lives with her sister in the city.

VI.

1. Where do you live?

2. Are you a teacher?

3. How do you travel to work?

4. What time does your school start?

5. Where are you going now?

V.

1. aren't

2. has

3. is unloading

4. must

5. front

6. do

7. benches

8. doesn't

9. an

10. in

7. a library

8. a cinema

9. an art gallery

10. a drug-store

6. travels

1. eating

2. stop

3. playing

4. brushes

5. listening

6. goes

7. live

8. wash

9. works

10. writing

1. A. listens

2. B. do

3. C. How

4. A. bicycle

5. A. in

6. C. help

-Tia phản xạ nằm trong mặt phẳng chứa tia tới và tia pháp tuyến

-Góc phản bằng góc tới.

Trong môi trường trong suốt và đồng tính, ánh sáng truyền đi theo đường thẳng