.

．—Dad，I’m worrying about my road test！

—Cheer up，dear! There___________be any difficulty about passing it since you have practised a

lot in the driving school．

A．mustn’t

B．shan’t

C．needn’t

D．shouldn’t

机动车在道路上发生故障难以移动时要在车后50米以内设置警告标志。