课程咨询

GRE首页 GRE课程 GRE动态 0元讲座 GRE模考网站

新东方在线 > GRE > GRE阅读 > 正文
扫码关注掌握一手留学资讯

扫码关注掌握一手留学资讯

回复XDF免费领

水平测试和备考资料

扫码关注公众号

GRE阅读练习：科学家的新发现

2019-09-04 15:08:00来源：网络

　　为了帮助大家高效备考GRE，新东方在线GRE频道为大家带来GRE阅读练习：科学家的新发现，希望对大家GRE备考有所帮助。更多精彩尽请关注新东方在线GRE频道!

　　In laboratories, healthy adult human brain neuronstypically live no more than a few hours, makingextensive research impossible. Furthermore,scientists' inability to reproduce healthy neuronshas prevented the use of neurons in experimentaltreatments of severe neurological disorders.

　　However, two researchers at the Johns HopkinsUniversity School of Medicine have successfully maintained mature, human brain neurons inlong-term cultures by using cells obtained during surgery on an 18-month-old victim ofunilateral megalencephaly. The rare disorder, in which one side of the brain grows substantiallylarger than the other, occurs when neurons in the abnormal hemisphere undergo too manycell divisions before they mature. The neuronal imbalance in the brain of the infant causedseizures, prompting surgeons to remove the enlarged hemisphere---a treatment that hasproven successful in similar cases. The researchers then took neurons from the excised brainmatter and placed them in a blood-rich culture medium. After days, many of the cells had died,but a few continued to grow and divide. Nineteen months later, the team had subculturedcolonies of neurons onto new culture plates more than 20 times, with no significant changes incellular appearance or growth characteristics.

　　Scientists still don't know what triggers the proliferation of neurons in unilateralmegalencephaly. The neurons cultivated at Johns Hopkins---unlike those culled from tumorsare not cancerous, and accordingly are much more valuable as research tools. Finally, theexperiment presents the possibility that such neurons could be used in experimentaltreatments that currently use fetal brain cells, sidestepping an uncomfortable ethical issue.

　　Which sentence in the second paragraph, in which the author makes a conclusion, isnot supported with any factual or anecdotal evidence?

　　A.will allow researchers to expand their knowledge of neurological workings

　　B.is necessary to cure unilateral megalencephaly

　　C.is a viable medical procedure in some cases

　　D.is usually performed on infants who suffer from unilateral megalencephaly

　　E.is a rare procedure that is performed as a last resort

　　The passage supplies information to answer which of the following questions?

　　A.How old is the average unilateral megalencephaly patient?

　　B.Can fetal brain cells be used to treat unilateral megalencephaly?

　　C.Have scientists found a way to allow cells from victims of unilateral megalencephaly to existoutside of the body?

　　D.How long can neurons culled from tumors be sustained outside the body?

　　E.Will scientists find further experimental uses for neurons culled from unilateralmegalencephaly victims?

　　In the second paragraph, select the sentence in which a term is introduced thatrequires elucidation in a later sentence.

　　正确答案

　　1C

　　2C

　　3However, two researchers at theJohns Hopkins University School of Medicinehave successfully maintained mature, humanbrain neurons in long-term cultures by usingcells obtained during surgery on an 18-month-old victim of unilateral megalencephaly.

　　以上就是关于“GRE阅读练习：科学家的新发现”的内容，更多精彩内容，请关注GRE频道!


本文关键字: GRE阅读 GRE

添加新东方美研助教回复【GRE】获取

模考真题|写作题库|阅读机经|佛脚词汇

更多资料

添加美研助教号，
回复【GRE】获取备考必看资料包

  • 1.打开手机微信【扫一扫】，识别上方二维码；
  • 2.点击【添加美研助教号】，回复对应关键字领取学习资料。
更多>>
更多内容

关注新东方美研助教

回复【GRE】获取备考必看资料包

新东方美研备考资料
GRE/GMAT直播精讲小班 GRE/GMAT精讲智能系统课 托福直播/精讲课（30天/60天）
更多>>
更多惊喜>>

添加美研助教号，
回复【GRE】获取备考必看资料包

  • 1.打开手机微信【扫一扫】，识别上方二维码；
  • 2.点击【添加美研助教号】，回复对应关键字领取学习资料。
更多>>
更多资料
我要
反馈 返回
首页
  • 1
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7
  • 8
  • 9
  • 10