一种细菌的半径约为0.000045米，用科学记数法表示为（）米．

声音是一种物理信号，计算机要对它进行处理，必须将它表示成二进制数字的编码形式。图1是将模拟声音信号进行数字化的过程，其中步骤①和②对应的操作分别是( )。

A．量化、取样

B．取样、压缩

C．量化、压缩

D．取样、量化

下列是各物质所含的少量杂质（括号中物质）以及除去这些杂质所选用的试剂或操作方法，其中正确的是 [ ]

A．氯化钠溶液（氯化镁）-- 加入适量烧碱溶液，再过滤    

B．硝酸钠溶液（硫酸钠）--  加入适量氯化钡溶液．再过滤    

C．熟石灰（石灰石）--  高温煅烧

D．二氧化碳（一氧化碳）-- 通过澄清石灰水

速递查验平台系统往来信息将作为查验质量判定及赔偿依据，如果疑难邮件未征询就擅自（），引起用户投诉，相关局为责任局。

A、决定

B、解决

C、退回

D、承诺

《安全生产法》对安全生产教育培训作出了明确规定，下列为第二十一条规定的是( )。

A．生产经营单位采用新工艺、新技术、新材料或者使用新设备，必须了解、掌握其安全技术特性，采取有效的安全防护措施，并对从业人员进行专门的安全教育和培训
B．生产经营单位应当对从业人员进行安全生产教育和培训，保证从业人员具备必要的安全生产知识，熟悉有关的安全生产规章制度和安全操作规程，掌握本岗位的安全操作技能。未经安全生产教育和培训合格的从业人员，不得上岗作业
C．生产经营单位的主要负责人和安全生产管理人员必须具备与本单位所从事的生产经营活动相应的安全生产知识和管理能力。危险物品的生产、经营、储存单位以及矿山、建筑施工单位的主要负责人和安全生产管理人员，应当由有关主管部门对其安全生产知识和管理能力考核合格后方可任职
D．生产经营单位应当教育和督促从业人员严格执行本单位的安全生产规章制度和安全操作规程，并向从业人员如实告知作业场所和工作岗位存在的危险因素、防范措施以及事故应急措施

Anthropology is the study of human beings as creatures of society. It (1) its attention upon those. physical characteristics and industrial techniques, those conventions and values, which (2) one community from all others that belong to a different tradition.

The distinguishing mark of anthropology among the social sciences is that it includes for serious study other societies (3) our own. For its purposes any social (4) of mating and reproduction is as significant as our own. To the anthropologist our customs and those of a New Guinea tribe are two possible social schemes for (5) a common problem, and in so far as he remains an anthropologist he is (6) to avoid any weighting of one (7) the other. He is interested in human behavior, not as it is shaped by one tradition, our own, but as it has been shaped by any tradition (8) He is interested in a wide (9) of custom that is found in various cultures, and his object is to understand the way in which these cultures change and (10) , the different forms through which they express themselves and the (11) in which the customs of any peoples function in the lives of the (12) .

Now custom has not been commonly regarded as a (13) of any great moment. The inner workings of our own brains we feel to be uniquely (14) of investigation, but custom, we have a way of thinking, is behavior at its most commonplace. (15) , it is the other way round. Traditional custom is a mass of detailed behavior more astonishing than (16) any one person can ever evolve in individual actions. Yet that is a rather (17) aspect of the matter. The fact (18) first rate importance is the predominant role that custom (19) in experience and belief, and the very great varieties it may (20)

7（）

A. in favor of

B. instead of

C. rather than

D. in contrast with