当农业技术商品的需求价格弹性e的绝对值等于2时，则提高技术商品价格对销售收入最大化的

Computers are useful machines. They can help people a lot in their daily life. For example, they can help people to save much time to do more work, and they can help people to work out many problems they can't do easily. Our country asks everyone to learn to use computers before the twenty-first century, except the old people.

Today more and more families own computers. Parents buy computers for their children. They hope computers can help them improve their studies in school. However, many of their children use computers to play games, to watch videos or to sing. The teachers and parents complain that computers can not help children to study but make them fall behind. So computers are locked in boxes by parents.

In some other countries, even some scientists also hate computers. They say computers let millions of people lose their jobs or bring them a lot of trouble. Will computers really bring trouble to people or can they bring people happiness?

It will be decided by today's students themselves!

小题1:Why do we say the computer is a useful machine? Because ______. 

A．our country asks us to learn it

B．it can help us a lot

C．we can use it to play games

D．it can help us to find jobs小题2:What do many teachers and parents complain about? They complain that ______ .  

A．their students and children use computers to study.

B．computers let them lose their jobs

C．computers make their students and children fall behind

D．computers bring people a lot of trouble小题3:How do you understand the last sentence of this passage? I think it means ______. 

A．computers are used by people

B．people can live well without computers

C．one must decide how to use computer

D．computers are strange machines

已知水结成冰的温度是0℃，酒精冻结的温度是-117℃．现有一杯酒精的温度为12℃，放在一个制冷装置里、每分钟温度可降低1.6℃，要使这杯酒精冻结，需要几分钟？（精确到0.1分钟）

绞窄性疝与嵌顿性疝的主要区别是（）

A.疝块的大小

B.疝块有无压痛

C.是否出现肠梗阻

D.疝内容物能否回纳

E.疝内容物有无血运障碍

骶岬是骨盆内测量的重要指示点，是第几骶椎向前突出的部分

A．第三
B．第二
C．第六
D．第四
E．第一

天线伸出铁塔平台的距离应不小于（）米，全向天线伸出塔体的距离应不小于（）米。

A.1；1.5

B.1；2

C.2；1.5

D.2；2