正常运行时不可能出现爆炸性气体环境，如果出现也是偶然发生并且是短时间存在的场所属于( )。
A．0区 B．1区C．2区 D．11区
参考答案：C
在一本300页的书中，数字“1”在书中出现了多少次( )。
A．140
B．160
C．180
D．200
—Nobody will become a hero without the help of others. —That's true.（）
A. Practice makes perfect.
B. One tree can't make a forest.
C. Where there is a will, there is a way.
D. above all
