For the safety everyone obey the traffic rules when he is driving or walking.A. needB. m

问题补充：

For the safety, everyone obey the traffic rules when he is driving or walking.

A. need

B. must

C. may

D. could

答案：

A. need

(答案→)B. must

C. may

D. could

解析：句意：为了安全，每个人必须遵守交通安全，当他开车或走路的时候，A. need需要； B. must必须； C. may 可以；D. could能会；结合语境故选B