可一次钻出的孔径一般为（）。 ["<Φ12mm","<Φ24mm","<Φ30mm"]
he training is（）for every type of communication. ["valueless","invaluable","worthless","inworth"]
起重机工作类型与安全有着（）的关系。 ["一定","一般","十分密切"]
You（）a big step toward overcoming stage fright if you（）positively ["take；think","will take；will think","take；will think","will take；think"]
简述CRH380B型动车组受电弓的切除操作。
简述CRH380B型动车组转向架监控环路的作用。
