每年夏季，莆田市午后多雷阵雨，其降水类型属（　　）

A．地形雨

B．对流雨

C．台风雨

D．锋面雨

The public transport system in Beijing is very good now, so there _____be any difficulty in traveling around the city.

A．couldn’t

B．mustn’t

C．needn’t

D．shouldn’t