轨道安装作业时，所有施工人员都应戴好（）。
A、安全带；
B、工具袋；
C、防静电服；
D、安全帽
参考答案：D
To help others is more valuable than anything else. ______ we show our love and care to others,
the world will be full of happiness and pleasure. [ ]
A. As long as
B. As many as
C. As tall as
井下爆破器材发放硐室存放的雷管不应超过（）。
A.1000发
B.2000发
C.5000发
