在下列存储器中，访问速度最快的是( )。

A．硬盘存储器
B．软盘存储器
C．磁带存储器
D．半导体RAM(内存储器)

— Excuse me, could you tell me        ?

— Certainly. In half an hour.

A．when the high speed train would arrive

B．when the high speed train will arrive

C．when would the high speed train arrive

D．when will the high speed train arrive