The bicycle riders___weasr helmets.a.haven't to b.mustn't c.don't to have to d.don't have to

问题描述:

The bicycle riders___weasr helmets.a.haven't to b.mustn't c.don't to have to d.don't have to

d

D,这句话的意思是骑自行车的人没有必要带头盔