Stop! You can never touch this machine when it , it is very dangerous.
A. has been operated
B. will be operated
C. is operated
D. is being operated
网友回答
A. has been operated
B. will be operated
C. is operated
(答案→)D. is being operated
解析： 考查时态及语态。句意：停止，你根本不能触摸这台机器当它正在被操作的时候，它非常的危险。根据语义机器被操作的时候应用现在进行时的被动语态。故选D。