为了确保安全操作，操作工应严格执行的“三不发”为（）。
A.看准
B.说准
C.听准
D.发准信号
参考答案：A, C, D
He has bought a new car. It _______ be very expensive. [ ]
A. can
B. can't
C. must
D. mustn't
对于非营运小型、微型载客汽车GB21861-2014规定不再检验驻车制动。
