—Why, my new computer is rubbish! Five hours has passed and it still hasn’t finished the downloading.

—Don’t worry. You know, sometimes the Internet ________ be very slow.

A．can

B．may

C．should

D．must

下列四个寄存器中，不能用来作为间接寻址方式的寄存器是（）

A.CX

B.BX

C.BP

D.DI