The other day，my friend John drove his car down the street at _______I thought was a dangerous speed and   surprised everyone in the car.

A．which，that

B．which，it

C．as，which

D．what，that

假如没有重力，以下现象中可能发生的是 [ ]

A．人从地面向上跳起后，一定能落回地面

B．水将从高处向低处流

C．空气中将飘浮着许多杂物

D．高台跳水运动员比赛能继续进行