我国测量标准如何分类?
参考答案:
根据管理需要,我国将测量标准分为计量基准、计量标准和标准物质三类。
固定资产投资经济效益指标反映的是()
A.投资活动的规模
B.投资活动的成果
C.投入与产出之间的关系及其影响因素
D.投资活动的综合效益
Will there always be 31 water? When you consider how necessary water is to each and every one of us and to all 32 (live) things, and when you observe how man has mismanaged other 33 (nature) resources, you may have reason to worry. Man has badly polluted his sources of water 34 Earth. And he uses more and more water each day. Can man learn to treat 35 (pollute) water for reuse fast enough 36 (keep) pace with the world’s technology and 37 (grow) population?
At the present time there is no serious shortage of water in the United States. Water, however, is not 38 able to meet all the local needs. Some areas, such as the southwestern part of our country, get less rain than 39 . In these areas, water must be brought in from 40 outside. Los Angeles, for example, must obtain its water from sources hundreds of miles away in the Colorado River and the rivers of northern California.