- Do you know where my address book is?

　　　　- It________ be in the hall cupboard. I think I saw it this morning.

A．could

B．can

C．will

D．must

在UNIX系统中，下列命令中哪些可以用来显示文件的内容（）

A、type

B、cat

C、pg

D、pr

E、more

F、print