由|x|=3得x=±3,
①当x=3时,原式=|x+3|-|x-3|=x+3+x-3=6,
②当x=-3时,原式=-6,
∴原式=±6.
--Tom, do you know there _________ a sports meeting next Thursday?
--Sorry, I forgot to tell you.
A.are going be
B.is going to have
C.will have
D.will be
双线半自动闭塞列车到达接车站由于接车方面的轨道电路故障接车站,应使用()按钮才能办理闭塞机复原。
A.复原
B.故障
C.闭塞
D.进路