According to a survey, most of the coalmine accidents are caused by imperfect mine ventilation.

根据调查显示，大部分的煤矿事故都与矿井通风系统不完善有直接的关系。

youdao

According to a survey, most of the coalmine accidents are caused by imperfect mine ventilation.

根据调查显示，大部分的煤矿事故都与矿井通风系统不完善有直接的关系。

youdao