His______behavior macle everyone nervous. He was always rushing to open doors and perform other small tasks, apologizing unnecessarily for any inconvenience that he might have caused.

A．oblivious

B．observant

C．obsequious

D．obsolescent

用于将汇编语言转换为机器语言的软件是( )。

A．编译程序

B．解释程序

C．汇编程序

D．监测程序