—I came to your office yesterday morning, but nobody was in.

—Oh, we ________ a meeting in the meeting room. [ ]

A. have had

B. had

C. were having

D. had had

为了提高软件开发效率，开发软件时应尽量采用( )。

A．汇编语言
B．机器语言
C．指令系统
D．高级语言