IT接地系统应装设绝缘监视以及接地故障报警或显示装置。( )
参考答案：对
—Hello, this is Lily speaking.Could I speak to Mr. Black?
—…Sorry. He ______ the Xuanwu Lake Park. [ ]
A. has been to
B. went to
C. has gone to
D. will go to
某一项年金前6年年初没有流入，后6年每年年初流入10000元，则该递延年金的递延期是( )年。
A．5
B．6
C．4
D．3
