把一小块白磷放在空气中加热到40℃时就能燃烧，但将其置于盛有80℃水的烧杯中，却

(一)

某建设项目的热力管道工程，可以采用20cm和30cm两种管径。工程费用和水泵的运行费用如下表所示。两种管道的寿命期相同，都是15年，15年后的处理价格都是初期投资额的10%，其他条件相同。已知：(P/A，10%，15)=7.6061，(P/F，10%，15)=0.2394，(A/P，10%，15)=0.13147，(F/A，10%，15)=31.7725，(F/p，10%，15)=4.1772。回答下述问题。

管径(cm)	20	30
配管工程费(万元) 每年水泵运行费(万元)	1800 350	2400 200

当资本的利率依然为10%，则20cm直径的方案净年值为( )万元。

A．581

B．502

C．508

D．543

阅读理解。

     Which country is the biggest  country in the world? Well,  look at the map and you'll  know it is Russia.

Then the following are Canada, China, the USA and Brazil. Among them, China has the largest number of people , with  the population reaching 1.3 billion. Canada has the longest coastline.  It is long enough to go

around the earth six times. What is the largest island in the world, do you know?  Is that Hawaii? No, it is

much smaller than the largest island in the world-Greenland.Greenland is to the northeast of Canada. 81% of  its land is covered with ice.  It is very cold  there,  so there are only  about 56,000  people living on the

land.

1.  What is the fifth largest country in the world?

A. China    

B. America  

C. Brazil    

D. Canada

2.   A. Which country has the largest number of people?               

A. Russia    

B. Canada    

C. China    

D. America

3.   How many times can Canada's coastline go around the earth?

A. Five times    

B. Six times  

C. Seven times  

D. Four times

4.  What is the largest island in the world?          

A.  Hawaii    

B. Greenland    

C. Taiwan    

D. Hainan Island

5.  How much of Greenland's land is covered with ice?

A. 80%    

B. 81%    

C. 18%    

D. 13%

两条或两条以上的道路在同一平面上相交称为（）。

A.平面交叉

B.立体交叉

C.空间交叉

D.分离交叉

酒精灯和酒精喷灯都以乙醇为燃料，灯内的乙醇量不能超过其总容积的（）。

A、40910

B、40942

C、40972

D、40973

电力猫必须配对使用，并且可以一对多使用。