沿运煤皮带各重要工作地点，应设有（）
A、照明
B、护栏
C、禁止通行警告牌
D、事故停机按钮及皮带启动警告铃
参考答案：D
We ________ our lives had it not been for the policeman.
A．would have lost
B．should lose
C．might lose
D．had lost
