有甲、乙两个装置,下列说法错误的是 A.甲、乙装置中,Zn的质量均减小 B.甲

题型:选择题

问题:

有甲、乙两个装置,下列说法错误的是

A.甲、乙装置中,Zn的质量均减小

B.甲、乙装置中,Cu上均有气泡产生

C.化学反应速率乙 > 甲

D.甲中H+移向Zn,乙中SO42-移向Zn

考点:原电池原理的应用原电池的形成条件原电池原理
题型:选择题

某人站在平面镜前2米处,此时人与像间的距离是_______米,人以1米/秒速度远离平面镜,人在镜中像的大小将_______ ,5秒钟后人与像间的距离是_______米。

题型:选择题

D

Among rich countries, people in the United States work the longest hours. They work much longer than in Europe. This difference is quite surprising because productivity per hour worked is the same in the United States as it is in France, Spain and Germany, and it is growing at a similar speed.

In most countries and at most times in history, as people have become richer they have chosen to work less. In other words they have decided to "spend" a part of their extra income on a fuller personal life. Over the last fifty years Europeans have continued this pattern, and hours of work have fallen sharply. But not in the United States. We do not fully know why this is. One reason may be greatly lower taxes in America, which increase the rewards to work. Another may be more satisfying work, or less satisfying personal lives.

Longer hours do of course increase the GDP (国内生产总值). So the United States has produced more per worker than, say, France. The United States also has more of its people at work, while in France many more mothers and older workers have decided to stay at home. The overall result is that American GDP per head is 40% higher than in France, even though productivity per hour worked is the same.

It is not clear which of the two situations is better. As we have seen, work has to be compared with other values like family life, which often get lost in its interest. It is too early to explain the different trends (趋势)in happiness over time in different countries. But it is a disappointing idea that in the United States happiness has made no progress since 1975, while it has risen in Europe. Could this have anything to do with trends in the work-life balance ?

51. From the text we know that the author __________.

A. believes that longer working hours is better

B. prefers shorter working hours to longer ones

C. says nothing certain about which pattern is better

D. thinks neither of the patterns is good

52. Which of the following countries has more of its people at work?

A. Spain.      B. France.    C. Germany.    D. America.

53. In the last paragraph, the underlined word "which" refers to_________.

A. family life  B. situations  C. other values  D. trends

54. What message can we get from the text?

A. The GDP of Europe, is higher than that of America.

B. Two possible reasons are given for working longer hours in the US.

C. People all over the world choose to work less when they are richer.

D. Americans are happier than Europeans.

55. Which of the following would be the best title for the text?

A. Americans and Europeans.              B. Staying at Home.

C. Work and Productivity.                 D. Work and Happiness.

题型:选择题

供电企业不能如期确定供电方案时应向用户说明原因。

题型:选择题

(737-800)飞行中什么时候,EEC自动选择进近慢车()

A.飞行下降低于15,000英尺MSL(平均海平面)且当EEC接收襟翼及防冰信号失败时

B.襟翼处于着陆形态或发动机起动电门放在CONT或FLT时

C.襟翼处于着陆形态或任一个发动机防冰处于开时

D.A、C都正确

题型:选择题

更换有功变送器的操作过程。

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