在轨道车与接触网作业车运行中，司机、副司机呼唤应答时，单臂拢拳屈伸表示注意信号或要求注意。
1、正确正确
暂无解析
No sooner had we reached home ________ a violent storm broke out.
Since we have a focused subject ，we should not talk ________.
Robots differ from automatic machines ________ after completion of one specific task，they can be reprogrammed by a computer to do another one.
The largest and smallest states of the United States are ________.
Why do you blame him for his poor judgment on the matter ______ he really needs is encouragement?
