I actually believe that you_______ in hospital now if you had worn seat belts at that time.

A．weren’t

B．had not been

C．wouldn’t have been

D．wouldn’t be

有关通风和空气调节系统中管道的敷设方式正确的是（）。

A.对排除有燃烧或爆炸危险气体、蒸汽和粉尘的排风系统，其排风管应为暗装

B.乙、丙类厂房内的送、排风管道不宜分层设置

C.甲类厂房内的送、排风管道宜分层设置

D.厂房内用于有爆炸危险场所的排风管道，可穿过防火墙和有爆炸危险的房间隔墙