You must never take your helmet off while you are...

Câu hỏi: You must never take your helmet off while you are riding a motor.

A. If you are riding a motor, you needn't wear a helmet.

B. Helmets must be worn at all times when you are riding a motor.

C. When you are riding a motor, wearing a helmet is not a must.

D. You shouldn't wear a helmet whenever you are riding a motor.