Some cyclists make the ______ that traffic laws do not ______ them. It is not true, _____.

A．assumption; apply to; though

B．thought; apply to; however

C．assuming; apply for; though

D．idea; apply for; however

粉状乳化炸药生产的火灾爆炸危险因素主要来自( )。

A．物质危险性
B．油相材料的配制
C．装药包装的结构
D．安全管理制度不健全