1. You had better/should go to bed early.

2. I plan to go to Sam Son beach.

3. She's going to go shopping.

4. I need to buy some apples.

5. Homework needs to be done by her.

6. The house needs painting.

7. It's easy for me to do Maths homework.

--> Doing Maths homework is easy for me.

Vận tốc truyền âm trong không khí là: 340m/s.

Khoảng cách từ nơi mình đứng đến chỗ sét đánh là:

S= v.t= 340.3= 1020 (m).

Đáp số: 1020 m.