| Birds are literally half-asleep--with
one brain hemisphere alert and the other sleeping, according to a new study of
sleeping ducks. Earlier Studies have documented half-brain sleep in a wide range of birds. The brain hemispheres take turns sinking into the sleep stage characterized by slow brain waves. The eye controlled by the sleeping hemisphere keeps shut, while the wakeful hemisphere’s eye stays open and alert. Birds also can sleep with both hemispheres resting at once. Decades of studies of bird flocks led researchers to predict extra alertness in the more vulnerable, end-of-the-row sleepers. Sure enough, the end birds tended to watch carefully on the side away from their companions. Ducks in the inner spots showed no preference for gaze direction. Also, birds dozing (打盹) at the end of the line resorted to single- A. half-brain sleep is found in all kinds of birds B. half-brain sleep is characterized by accelerated brain waves C. birds can control their half-brain sleep consciously D. birds always sleep with the whole of their brain at rest [判断题]将伤员身上潮湿的衣服剪去后用干燥柔软的衣服覆盖，不得烤火，但可以搓雪。
A.正确 B.错误 [判断题]竖流式沉淀池其颗粒的沉速为其本身沉速与水流上升速度相等。
[多选题]车体入库后对餐车焚火锅炉、炉灶、茶炉有何规定
A.车体入库后，焚火锅炉、必须压火 B.炉灶、茶炉必须灭火，炉灰清理干净入袋管理 C.看车人员要经常查看锅炉压火状况，如有燃烧情况，立即重新压火，杜绝火患 [单项选择]牙周炎的叙述不正确的是( )
A. 菌斑是牙周炎主要原因 B. 牙石是口腔卫生不良主要标志 C. 早期病变内胶原的破坏丧失可达30%～40% D. 始发期为急性渗出性炎症 E. 进展期为持续性炎性破坏过程 [单选题]车道已使用的票据( )会自动核销一次
A.每1分钟 B.A.每5分钟 C.A.每10分钟 D.A.每15分钟 [判断题]速度型压缩机有两种结构型式：往复活塞式（简称活塞式）和回转式。
[单选题]下列空调系统的空气可以循环使用的是( )
A.麻醉药品生产区 B.病原体操作区 C.放射性药品生产区 D.生产中使用有机溶媒,且 因气体积聚可构成爆炸或火灾危险的工序 [填空题]加油站工作实行（）。
[单选题] 全面质量管理的基本核心是强调提高人员的工作质量,( ),达到全面提高企业和社会经济效益的目的。
A.保证和提高产品质量 B.确保完成生产任务 C.加强生产过程管理 D.保证售后服务 [单选题]堵水施工下井油管前必须用通径规通过。φ73mm油管使用的通径规直径( )，长度800～1200mm。
A.40 mm B.59 mm C.20 mm D.62 mm 我来回答: 提交
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