调车表示器向调车区显示一个()灯光,准许机车、车辆自调车区向牵出线运行。
A.绿色
B.蓝色
C.白色
D.黄色
参考答案:C
Both parents and teachers work hard at either preventing failure or protecting the children from the knowledge_______ they have failed.
A.where
B.why
C.which
D.that
简述汉陵十景的内容。