列车断钩后起紧急制动时，应是（）先动作，（）后动作。
参考答案：紧急阀94；电动放风阀
Bill Smith can play ____ soccer. His brother can play ____ violin,
but they often play ____ yo-yo together. [ ]
A. the, the, with
B. a, the, for
C. /, the, with
D. the, / , for
国家规划中，明确提出打造首都经济圈，这个规划出自（）
A.“十一五”规划
B.“十二五”规划
C.北京城市总体规划
D.奥运行动规划
