问题 填空题

在标定标准溶液浓度时,平行试验不得少于8次,2人各做四平行,每人四平行测定结果极差的相对值不得大于重复性临界极差〔CrR95(4)〕的相对值(),两人八平行测定结果极差的相对值不得大于重复性临界极差〔CrR95(8)〕的相对值0.18%,取两人八平行测定结果的平均值为测定结果。在运算过程中保留五位有效数字,浓度值报出结果取四位有效数字。

答案

参考答案:0.15%

解析:

GB601-2002中规定标准溶液的标定“须两人进行实验,分别各做四平行,每人四平行测定结果极差的相对 值,不得大于重复性临界极差[C,Rss(4 ) 」的相对值0.15%,两人共八平行测定结果极差的相对值不得 大于重复性临界极差[C.Rs5(8)」的相对值0.18%。

单项选择题 A1型题
单项选择题

In our society, we must communicate with other people. A great deal of communicating is performed on a person-to-person (1) by the simple means of speech. If we travel in buses, stand in football match (2) , we are likely to have conversations (3) we give information or opinions, and sometimes have our views (4) by other members of society.

Face-to-face contact is (5) the only form of communication, and during the last two hundred years the (6) of mass communication has become one of the dominating factors of contemporary society. Two things, (7) others, have caused the enormous growth of the communication industry. Firstly, inventiveness has (8) advances in printing, photography and so on. Secondly, speed has revolutionized the (9) and reception of communications so that local news often (10) a back seat to national news.

No longer is the possession of information (11) to a privileged minority. Forty years ago people used to (12) to the cinema, but now far more people sit at home and turn on the TV to watch a program that (13) into millions of houses. Communication is no longer merely concerned (14) the transmission of information. The modern communications industry influences the way people live in society and broadens their horizons by allowing (15) to information, education and entertainment. The printing, broadcasting and advertising industries are all (16) with informing, educating and entertaining. (17) a great deal of the material communicated by the mass media is very valuable to the individual and to the society (18) which he is a part, the vast modern network of communications is (19) to abuse. However, the mass media are with us for better, for worse, and there is no turning (20) .

19()

A.possible

B.likely

C.close

D.open