驼峰自动集中是驼峰调车场的自动控制设备,对道岔、信号和()都实行程序控制。
A.减速器
B.减速顶
C.停车点
D.脱鞋道岔
参考答案:A
有关托盘与端托的描述正确的是()。
A.根据托盘形状分类有长方形、圆形两种
B.长方形或圆形大托盘一般用于传菜和搬运较重物品
C.中圆形托盘:一般用于摆台、酒水服务、撤换餐碟和换烟缸等
D.重托主要用于托运大型菜点、酒水和盘碟
E.端托按所托物品的轻重分轻托和重托两种
Most geologists believe oil results from chemical transformations of hydrocarbons derived from organisms buried under ancient seas. Suppose, instead, that oil actually results from bacterial action on other complex hydrocarbons that are trapped within the Earth. As is well known, the volume of these hydrocarbons exceeds that of buried organisms. Therefore, our oil reserves would be greater than most geologists believe. Which of the following, if true, gives the pest support to the argument above about our oil reserves
A.Most geologists think optimistically about the Earth’s reserves of oil.
B.Most geologists have performed accurate chemical analyses on previously discovered oil reserves.
C.Ancient seas are buried within the Earth at many places where fossils are abundant.
D.The only bacteria yet found in oil reserves could have leaked down drill holes from surface contaminants.
E.(E) Chemical transformations reduce the volume of buried hydrocarbons derived from organisms by roughly the same proportion as bacterial action reduces the volume of other complex hydrocarbons.