饲料、饲料添加剂生产企业，应当有符合国家规定的安全、卫生要求的生产环境。
参考答案：对
—Why didn't you leave school? It's already eight o'clock.
—Because I _______ my homework yet. [ ]
A. wasn't finishing
B. wouldn't finish
C. haven't finished
D. wasn't finished
东风8B型机车柴油机装用的“大圆薄板”联轴节属于（）联轴节。
A、弹性
B、半弹性
C、刚性
D、半刚性
