empty area

• 采空区

empty area的用法和样例：

例句

1. This text to adopt the empty area gas public needed the advertent problem to make to elaborate detailedly.
   文中对采空区瓦斯民用需注意的问题作了详细的阐述。
2. The mined-out area due to underground mining is one of the main risk sources of mines.
   地下开采留下的大量采空区是影响矿山安全生产最主要的危险源之一。