若选拔优秀毕业生的条件是：年龄（age）小于19岁，三门功课总分（total）大于285分，其中有一门（mark）为100分，表达式应写为（）。

A:age〈19 and total〉285 and mark 1=100 or mark2=100 or mark 3=100 B:age〈19 and total〉285 or mark 1=100 or mark2=100 or mark 3=100 C:age〈19 and total〉285 and（mark1=100 or mark2=100 or mark 3=100） D:（age〈19 or total〉285）and（mark1=100 o rmark2=100 or mark 3=100）

In what way does free float differ from total float ？（）

A:Free float is the amount of total float that does not affect the end date, whereas total float is the accumulated amount of free float. B:There is no difference-the two terms are functionally equivalent. C:Free float is the amount of time that a schedule activity can be delayed without delaying the early start of any immediately following schedule activities, whereas total float is concerned with delays that do not affect the project finish date. D:An activity's free float is calculated by subtracting its total float from the critical path's total float.

In what way does free float differ from total float

A:Free float is the amount of total float that does not affect the end date, whereas total float is the accumulated amount of free floa B:There is no difference-the two terms are functionally equivalen C:Free float is the amount of time that a schedule activity can be delayed without delaying the early start of any immediately following schedule activities, whereas total float is concerned with delays that do not affect the project finish dat D:An activity's free float is calculated by subtracting its total float from the critical path's total floa

A
It is estimated that some seven hundred million people about half the world’s population are un able to read and write, and there are probably two hundred and fifty million more whose level of attainment(造诣、成就)is so slight that it barely qualifies a literacy(识字).
Recently the attack on illiteracy has been stepped up. A world plan has been drawn up by a committee of UNESCO experts in Paris, as part of the United Nations Development Decade, and an international conference on the subject has also been held. UNESCO stresses that functional literacy is the aim. People must learn the basic skills of responsible citizenship: the ability to read notices, newspapers, timetables, letters, price lists, to keep simple records and accounts, to sort out the significance of the information gathered, and to fill in forms.
The major areas of illiteracy are in Asia, and Central and South America. In Africa there are at least one hundred million illiterates, making up eighty to eighty-five per cent of the total population. In Europe the figure is about twenty-four million, most of them is Southern Europe, with Spain, Italy, Portugal, and Yugoslavia heading the list (the United Kingdom has about seven hundred thousand).

A:3.4% of the total population in the world B:2.5 % of the total illiterate in the world C:1.7% of the total population in the word D:1.7 % of the total illiterate in the world

Wind, wave and tides all suffer from the fact that they are variable sources of power output. For example, there will be times when due to windless days or calm seas—and both can occur for periods of several days even in the winter time—they are producing little or no power.
Insofar as this shortfall has to be made up by electricity from conventional power stations, these newer energy sources would not necessarily reduce the installed capacity of such conventional stations needed to meet the total demand on windless or calm days. What the newer sources will do is to save fuel that would otherwise be burned in conventional power stations.
Pumped storage reservoirs could in principle be used to counter this effect, but there 1 is not enough additional reservoir capacity available. We therefore face the same type of storage problem as in solar energy. Thus, unless some new method of energy storage can be developed or we move to the widespread use of a fuel like hydrogen, the wind and wave schemes will be at an economic disadvantage.

A:A reduction of the fuel consumed by conventional power stations. B:A reduction of the manpower required by conventional power stations. C:The total replacement of conventional power stations. D:The total replacement of conventional energy sources.

China National Cereals,Oils & Foodstuffs Import and Export Corparation,Shenzhen Branch,hereinafter called the （）,agree to sell and China Native Products INC,Los Angels,California, （）,hereinafter called the Buyers,agree to buy the under-mentioned goods subject to the terms and conditions stipulated （）:
1．Name of Commodity &Specifications:ZHONG HUA BRAND Salted Cucumber50 tins*200 grams
2．Quantity and Weight:100 Cartons/1000kg
3．（） price:C & F C3% Los Angeles or San Francisco US$20.00 Per carton
4．Amount:US$2000.00
5．Time of Shipment:During Oct./Nov.,2009
6．（）:In Cartons
7．Marks & No.:ZHONG HUA BRAND
Salted Cucumber
No.1-100
8．Loading （） and Destination:From Shenzhen,China to Los Angeles Or San Francisco
9．Insurance:To be （） by the Buyers
10．Terms of Payment:To be made against sight draft drawn under an irrevocable （）,for the total value of goods in US$2000.00,（） 10% more or less both in amount and quantity at Sellers’ s option,established through a bank which is mutually agreed by the two sides.
11．Inspection:Certificate of quality & weight and phytosanitary certificate （） by China Entry & Exit Inspection and Quarantine authorities shall beprovided to the Buyers.The quality and weight certified in the certificates are to be taken as final.

A:Buying B:Selling C:Total D:Unit

TOTAL命令的功能是________。

A:对数据表记录个数进行统计 B:对数据表字段个数进行统计 C:对数据表的内容进行合并 D:对数据表的某些数值型字段按指定关键字进行分类汇总

TOTAL命令的功能是______。

A:对数据表记录个数进行统计 B:对数据表字段个数进行统计 C:对数据表的内容进行合并 D:对数据表的某些数值型字段按指定关键字进行分类汇总