光面爆破的周边眼布置的越密越好。（）
参考答案：错
— Could you tell me ____ ?
— Certainly. In half an hour.
A．when will the high speed train arrive
B．when the high speed train will arrive
C．when would the high speed train arrive
D．when the high speed train would arrive
压车机构的作用是什么？
