题目内容
13．Scientists at Harvard University have recycled a kidney（‘肾）-in a rat．The researchers removed a kidney from a dead rat．Later，the renewed kidney was put into a living rat．It wasn't perfect．It did，however，show signs of working like a kidney should．"It's really beautiful work，"Edward Ross，a kidney researcher at the University of Florida in Gainesville，told Science News．He didn't work on the new study．
Kidneys are bean-shaped and act like guards in the body．They clean the blood by removing waste and extra water．Every day，an adult's kidneys filter（过滤） enough blood to fill a bathtub half full．Along the way，they produce eight cups of urine（尿） from that waste and water．When a person's kidneys fail，all of that waste stays in the body．Such patients can quickly become very sick and die，unless they are regularly connected to a machine that filters their blood．
At any given time，about 100，000people in the United States are waiting for a replacement kidney．But healthy donated kidneys are difficult to get．Either a living person must donate one，or a kidney must be removed from someone who just died and earlier had agreed to the donation．In either case，people receiving new kidneys face the risk that their bodies will reject the donated ones．
But there may be another option．Researchers use knowledge of living things to grow or improve tissue that can aid human health．Harald Ott's team at Harvard started with a"used"kidney．
Scientists added kidney cells from rats and blood vessel cells from people to the matrix（母体）．These cells attached themselves and began to multiply．Before long，they formed new kidney tissue．
The scientists placed this renewed kidney into another rat．There it produced a small amount of urine．This experiment shows that the lab-grown kidney can do at least some of the work performed by a healthy kidney．
The results are a promising first step toward helping people with serious kidney problems．"This is still very early，but they've come a long way，"Ross said．
33．What does Paragraph 3mainly talk about？C
A．The relationship between kidneys and health．
B．The difficulty of curing serious kidney diseases．
C．The function and importance of kidneys．
D．The methods of curing kidneys diseases．
34．For what purpose does the author use the figure 100，000in Paragraph 4？B
A．To stress used kidneys are hard to get．
B．To show the great need for healthy kidneys．
C．To explain many American people get kidney diseases．
D．To call on people to donate kidneys．
35．Which of the following is true according to the text？A
A．The scientists are satisfied with the result of the experiment．
B．Ross is a kidney expert who is involved in the experiment．
C．The function of the renewed kidney is the same as a healthy kidney．
D．The renewed kidney produced a great deal of urine．
分析 本文介绍了哈佛大学的科学家利用老鼠做的一个研究肾脏的实验，虽然实验不尽完美，但是它确实显示出像肾脏一样工作的迹象．实验的结果对于帮助严重肾脏问题的人迈出了有希望的第一步．文中还提及了肾脏的功能和重要性．
解答 33．C 主旨大意题．根据本段的Kidneys are bean-shaped and act like guards in the body．They clean the blood by removing waste andextra water．可知，肾脏呈豆状，肾脏就像身体里的卫士，通过清除废物和多余的水来净化血液．所以这段主要介绍肾脏的功能和重要性，故选C．
34．B 细节理解题．根据第四段的At any given time，about 100，000people in the United States are waiting for a replacement kidney．可知，在任何时候，美国大约有100000人在等待替换肾脏．所以作者用100，000这个数字是为了表明对健康的肾脏的需求量很大，故选B．
35．A 细节理解题．根据最后一段的The results are a promising first step towardhelping people with serious kidney problems．可知，这个结果是对帮助有严重肾脏问题的人迈出的有希望的第一步．所以科学家对这次实验的结果很满意，故选A．
点评 本文是科教类阅读，主要考查细节理解题和推理判断题．在做细节理解题时，首先根据题目要求迅速在文章里找出相应的段落、句子或短语．认真比较选项和文中细节的区别，在做推理判断题时不要以个人的主观想象代替文章的事实，要根据文章事实进行合乎逻辑的推理判断．
