物业服务企业资质等级分为（）。
A.特级
B.一级
C.二级
D.三级
E.四级
参考答案：B, C, D
---Where did you see the movie Life of Pi directed by Ang Lee?
---- It was in the cinema ________ I regularly go .
A．where
B．that
C．which
D．what
AF信号由内话系统至中继线过程中，LINE（MUX）将转换PTT命令为E&M信令，而LINE（RCE）将PTT命令转换为（）单音与AF信号混合。
A.2400HZ
B.26O0HZ
C.3000HZ
