CTCS-2级列控系统一般间隔2~3个闭塞分区在闭塞分区边界上设置()。
A.电气绝缘
B.警示标
C.无源应答器
D.有源应答器
参考答案:C
Child as he was, he ________ a good idea to solve the problem.
A.came up with
B.came about
C.came into
D.came out with
世界上第一部有声动画是()年拍摄的《汽船威利号》。