— Is that Jack speaking?

— Sorry, he isn't in right now. He       _ the cinema with his aunt.                [ ]

A. has been to        

B. has gone to

C. have been to        

D. have gone to

施工现场塔式起重机起重力矩限制器常见有（）等安全隐患。

A、力矩限制器失效

B、力矩限制器调整不准确

C、力矩限制器行程开关未按规定设置

D、力矩限制器人为放大