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问题 选择题

如图装置中，a、b试管内分别盛有食盐水和氯化铵溶液，各加入一块生铁片，放置一段时间．下列有关描述错误的是（　　）

A．红墨水柱两边的液面变为左低右高

B．两块生铁片均发生电化学腐蚀

C．两试管中相同的电极反应式为Fe→Fe2++2e-

D．a试管中发生了吸氧腐蚀，b试管中发生了析氢腐蚀

答案

A、左边试管中是中性溶液，发生吸氧腐蚀，右边试管中是酸性溶液发生析氢腐蚀，所以左边试管内气体的氧气减小，右边试管内气体的压强不大，导致U型管内红墨水左高右低，故A错误；

B、生铁中含有铁和碳，铁、碳和电解质溶液构成了原电池，所以发生电化学腐蚀，故B正确；

C、生铁的吸氧腐蚀和析氢腐蚀中都是铁作负极，负极上铁失电子发生氧化反应Fe-2e-→Fe2+，故C正确；

D、左边试管中是中性溶液，发生吸氧腐蚀，右边试管中是酸性溶液发生析氢腐蚀，故D正确．

故选A．

阅读理解
Harry’s father bought a magazine which gave its readers information about all kinds of products and helped them make the best choice while buying．
Harry borrowed his father’s magazine when he needed a new computer．“I’ll read it and choose the best one．” He said．
The magazine described these computers．
The DGT PC450
The BNK 975XF: AT $3，200
The CGP 8PT

This computer comes with lots of good software. However it does not have much memory and is rather slow．At $2，850 it’s not very good value for money.

This is the most expensive computer we tested．However it is also far the most reliable (可靠的)．It is very fast and has lots of memory．It is worth the extra money if you can afford it．

At only $1，900．It has lots of money and is quite fast．However it broke down twice while we were testing it and we cannot recommend (建议) it for reliability．
Harry chose the BNK 975XF．“I know it’s expensive，” he said，“but it will be with me for a long time and do everything I want it to do．”
小题1:Harry wants to buy a computer，so he borrowed ________ from his father．
A．a computer magazineB．a magazine about all kinds of products
C．a shopping bookD．a book about all kinds of computers
小题2:________ doesn’t have much memory and is rather slow．
A．The DGT PC450 B．The BNK 975XF
C．The CGP 8PTD．Harry’s computer
小题3:The CGP 8PT is ________ among the three kinds of computers．
A．the fastestB．the most expensive
C．the cheapestD．the slowest
小题4:Harry chose the BNK 975XF because ________．
A．it is the most expensiveB．it has lots of good software
C．it has much memoryD．it would work for him for a long time
小题5:．________ helped Harry to choose the computer．
A．His fatherB．His friendC．The shopkeeperD．The magazine
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单项选择题

在本金相等、计息的周期数相同时，如果利率相同，则通常情况下( )。 (计算的周期数大于1)

A．单利计息的利息少，复利计息的利息多

B．单利计息的利息多，复利计息的利息少

C．单利计息的利息与复利计息的利息一样多

D．无法知道
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