第一个周期的快波睡眠期持续时间为() ["5~10分钟","10~15分钟","15~20分钟","20~30分钟","30~40分钟"]
按安全操作要求,以下哪一种工件不允许在砂轮机上磨削作业?() ["铁棒","钢制零件","塑料内饰件","合金钻头"]
慢波睡眠分为几个阶段() ["1个","2个","3个","4个","5个"]
2012年睡眠日主题是() ["睡眠与女性","健康睡眠进社区","科学的睡眠消费","关注中老年睡眠","关注睡眠品质,关爱儿童睡眠"]
上弦月亮与太阳角度是多少度() ["A、45度","B、90度","C、135度","D、180度"]
试述企业管理体制三种基本模式的特点。