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问题 问答题

第一次测定铸铁里的声音是在巴黎用下列方法进行的：从铸铁管的一端敲一下钟，在管的另一端听到两次响声．若管长为748m，两次响声相隔2s，则声音在铸铁中1s传播多远？

答案

∵管长s=748m，空气中的声速是v声=340m/s，两次声响相隔时间t=2s，

∴

s
v空气
-
s
v铁
=t，

即：

748m
340m/s
-
748m
V铁
=2s，

解得：v铁=3740m/s．

答：声音在铸铁中1s传播3740m．

单项选择题

尿液浓缩稀释试验主要用于检查（）

A.远端肾小管功能

B.近端，远端肾小管及集合管

C.髓袢，远端肾小管和集合管

D.远端及近端肾小管功能

E.近端肾小管功能
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填空题

Part 3


Questions 19-25


·Read the following passage and answer questions 19-25.
·For questions 19-25, choose the correct answer A, B, C and D.
·Mark your answers on the Answer Sheet.
While still in its early stages, welfare reform has already been judged a great success in many states, at least UN is getting people off welfare, lt’s estimated that more than two million have left the roles since 1994.
In the past four years, welfare in rolls in Athens country has been cut in half. But 70 percent of the people who left in the past two years took jobs that paid less than $6 an hour. The result: The Athens country poverty rate still remains at more than 30 percent—twice the national average.
For advocates for the poor, that’s an indication that much more needs to be done.
"More people are getting jobs, but it’s not making their lives any better," says Kathy Lairn, a policy analyst at the center in budget and policy priorities in Washington.
Canter analysis of US census data nationwide found that between 1995 and 1996, a great percentage of single, fame-headed household were earning money on their own, but that average income for these households actually went down.
But for many, the fact that poor people are able to support themselves almost as well without government aid as they did with it is in itself a huge victory.
"Welfare was a poison. It was a toxin that was poisoning the family," says Rector, a welfare reform is changing the moral climate in low-income communities. It’s beginning to rebuild the work ethic, which is much more important.
Mr. Rector and others argued that once "the habit of dependency is cracked," then the country can make other policy changes aimed at improving living standards.

From the passage we can infer that before 1994 ______.

A．most of the people depended on government

B．most of the people took jobs

C．we don’t know as the passage didn’t say

D．most of the people live a richer life
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