为什么软底工作面支柱要“穿柱鞋”？
参考答案：
软底工作面支柱“穿鞋”支设可增加底板的受力面积，防止支柱钻底板，保证支柱初撑力及工作阻力达到要求。
Our company has been made one of the largest manufacturers in the field of chemical industry.
A．become, in
B．made, in field of
C．became, in the field
D．been made of, in
横穿轨道时注意事项？
