各种剪切设备上剪刀、下剪刀间都有间隙要求，间隙过小时，会使材料断裂部分挤坏，使剪床（）增加。
A、剪速
B、剪切力
C、负荷
D、振动
参考答案：C
Have you prepared for the sports meeting which ______ soon?
A. has taken place B. will be taken place
C. is to take place D is to be taken place
信息孤岛
