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问题 问答题

打开工作簿文件EX11．XLS(内容如下)，将工作表sheet1的A1：D1单元格合并为一个单元格，内容居中；计算“总计”行的内容，将工作表命名为“生产费用表”。

答案

参考答案：

解析：打开工作表。合并单元格。在B6中键入“=SUM(B3：B5)”公式，双击此单元格，出现公式，向石拖动右下角的实心方块填充到其他需要产生结果的单元格。

选择题

某温度下，向pH=6的纯水中加入一定量的盐酸，保持温度不变，测得溶液的pH=2。下列有关该溶液的叙述中不正确的是 [ ]

A.pH=6的纯水呈中性

B.该溶液中c(H+)=0.01 mol·L-1

C.该溶液中由水电离产生的c(H+)=10-10 mol·L-1

D.该温度下加入等体积pH=12的NaOH溶液，可恰好完全中和

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单项选择题

A weather map is an important tool for geographers. A succession of three of four maps presents a continuous picture of weather changes. Weather forecasts are able to determine the speed of air masses and fronts; to determine whether an individual pressure area is deepening or becoming shallow and whether a front is increasing or decreasing in intensity. They are also able to determine whether an air mass is retaining its original characteristics or taking on those of the surface over which it is moving. Thus, a most significant function of the map is to reveal a synoptic picture of conditions in the atmosphere at a given time.

All students of geography should be able to interpret a weather map accurately. Weather maps contain an enormous amount of information about weather conditions existing at the time of observation over a large geographical area. They reveal in a few minutes what otherwise would take hours to describe. The United States weather Bureau issues information about approaching storms, floods, frosts, droughts, and all climatic conditions in general. Twice a month it issues a 30-day "outlook" which is a rough guide to weather conditions likely to occur over broad areas of the United States. These 30-day outlooks are based upon an analysis of the upper air levels with often set the stage for the development of air masses, fronts, and storms.

Considerable effort is being exerted today to achieve more accurate weather predictions. With the use of electronic instruments and earth satellites, enormous gains have taken place recently in identifying and tracking storms over regions which have but few meteorological stations. Extensive experiments are also in progress for weather modification studies. But the limitations of weather modification have prevented meteorological results except in the seeding of super-cooled, upslope mountainous winds which have produced additional orographical precipitation on the windward side of mountain ranges. Nevertheless, they have provided a clearer understanding of the fundamentals of weather elements.

One characteristic of weather maps not mentioned by the author in this passage is（）

A. wind speed

B. thermal changes

C. fronts

D. barometric pressure
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