13.Scientists at Harvard University have recycled a kidney(‘腎)-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(過濾) 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(母體).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 本文介紹了哈佛大學的科學家利用老鼠做的一個研究腎臟的實驗,雖然實驗不盡完美,但是它確實顯示出像腎臟一樣工作的跡象.實驗的結(jié)果對于幫助嚴重腎臟問題的人邁出了有希望的第一步.文中還提及了腎臟的功能和重要性.
解答 33.C 主旨大意題.根據(jù)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,腎臟呈豆狀,腎臟就像身體里的衛(wèi)士,通過清除廢物和多余的水來凈化血液.所以這段主要介紹腎臟的功能和重要性,故選C.
34.B 細節(jié)理解題.根據(jù)第四段的At any given time,about 100,000people in the United States are waiting for a replacement kidney.可知,在任何時候,美國大約有100000人在等待替換腎臟.所以作者用100,000這個數(shù)字是為了表明對健康的腎臟的需求量很大,故選B.
35.A 細節(jié)理解題.根據(jù)最后一段的The results are a promising first step towardhelping people with serious kidney problems.可知,這個結(jié)果是對幫助有嚴重腎臟問題的人邁出的有希望的第一步.所以科學家對這次實驗的結(jié)果很滿意,故選A.
點評 本文是科教類閱讀,主要考查細節(jié)理解題和推理判斷題.在做細節(jié)理解題時,首先根據(jù)題目要求迅速在文章里找出相應(yīng)的段落、句子或短語.認真比較選項和文中細節(jié)的區(qū)別,在做推理判斷題時不要以個人的主觀想象代替文章的事實,要根據(jù)文章事實進行合乎邏輯的推理判斷.