问题 阅读理解与欣赏

阅读下面的文字,完成1-3题。

法科学家揭示T淋巴细胞“攻击”路线图

  新华社巴黎2月15日电 (记者卢苏燕)法国科学家最近成功拍摄下T淋巴细胞攻击肿瘤细胞的路线图,揭示了这种免疫细胞“作战”的全过程。这项成果将有助于提高癌症的治疗水平。

  据法国国家科学研究中心15日宣布,这项研究由法国居里研究所、法国国家健康与医学研究所及法国国家科学研究中心免疫专家和显微镜专家合作完成。专家们利用双光子显微镜拍摄下T淋巴细胞识别致病细胞包围并攻击致病细胞的整个过程。据称,这在世界上尚属首次。

  T淋巴细胞是机体免疫系统内功能最重要的一大类细胞群,这类细胞拥有识别肿瘤细胞等致病细胞抗原的能力,当发现这种抗原时,T淋巴细胞就会向致病细胞发起攻击,以特殊的酶杀死致病细胞。在法国科学家之前,科学界虽然知道T淋巴细胞在免疫系统中发挥的作用,但一直没能从细胞层面观察到被激活的T淋巴细胞的工作过程。

  法国科学家在研究和观察中发现,在祛除抗原的肿瘤中,无论肿瘤处于什么发育阶段,T淋巴细胞运动速度都很快,大约为每分钟10微米;相反,当把T淋巴细胞注入具有抗原的肿瘤细胞3至4天后,T淋巴细胞的运动速度明显减缓,而且经常停止不动,平均最快速度不超过每分钟4微米,在T淋巴细胞的作用下肿瘤停止发育。当肿瘤彻底萎缩后,T淋巴细胞又恢复以非常快的速度运动。

  研究人员由此总结说,存在致病抗原以及T淋巴细胞对这种抗原的识别是T淋巴细胞深入致病细胞和杀死致病细胞的前提。此外,T淋巴细胞运动速度的加快或是表明没有“敌”细胞即致病细胞,或是机体免疫系统出现问题,“打了败仗”。 据悉,法国科学家在这一领域的研究已经进行了多年。目前,他们正在对T淋巴细胞的作用及宫颈癌治疗进行临床研究。

1.对“T淋巴细胞”理解不准确的一项是(     )

A.T淋巴细胞是指一大类细胞群,它在动物机体免疫系统内具有重要功能。

B.T淋巴细胞拥有一种特殊的本领,就是它具有识别肿瘤细胞的能力。

C.科学界早在法国科学家的发现之前就已经知道了T淋巴细胞在免疫系统中发挥着重要作用。

D.当向致病细胞发起攻击的时候, T淋巴细胞是用一种特殊的酶来杀死致病细胞。

2.下列说法不符合文章原意的一项是(     )

A.最近,法国科学家利用双光子显微镜成功拍摄下T淋巴细胞识别致病细胞,包围并攻击致病细胞的路线图。

B.在祛除抗原的肿瘤中,T淋巴细胞会以很快的速度运动;当肿瘤彻底萎缩后, T淋巴细胞也会以非常快的速度运动。

C.把T淋巴细胞注入具有抗原的肿瘤细胞,3至4天后T淋巴细胞的运动速度就会明显减缓,甚至经常停止不动,在T淋巴细胞的作用下,肿瘤停止发育直至彻底萎缩。

D.T淋巴细胞运动速度的加快向我们发出信号:没有发现致病细胞。

3.根据全文信息,下列推断不恰当的一项是(     )

A.目前,法国科学家正在对T淋巴细胞的作用及宫颈癌治疗进行临床研究,不久的将来人类有望依据他们的科研成果彻底根治癌症等疾病。

B.法国科学家的研究,从细胞层面观察到被激活的T淋巴细胞的工作过程,使人类对T淋巴细胞的研究向前迈出了一大步。

C.根据法国科学家的研究,T淋巴细胞深入致病细胞和杀死致病细胞是有前提的,所以不能盲目依据T淋巴细胞的速度快慢来判断人体是否存在肿瘤细胞。

D.据法国科学家研究中心15日宣布的消息,这项研究是由四方共同完成的,这也说明在科技高度发达的今天,合作是当代科学研究的必然选择。

答案

1.B

2.D

3.A

阅读理解

A new report says only about half of all students in the main school systems of America’s largest cities finish high school. The report notes higher rates of graduation — over 70% —in areas surrounding the cities. Researchers studied high school graduation rates from the 2003, 2004 school year. They also identified the nation’s fifty largest cities. The largest, New York City, had a population of more than eight million. The smallest city was Wichita, Kansas. It had about three hundred and sixty thousand people.

Researchers used a system of measurement called the cumulative promotion index to find graduation rates. School officials in many of the cities studied said the resulting numbers were too low. That is because different areas use different methods to find graduation rates. Critics say many methods do not give a true picture of the number of students who leave high school before finishing.

Other studies have put the national graduation rate at about 70%. But experts agree that too many students are not completing high school. They estimate the number at more than one million each year. The report was prepared for America’s Promise Alliance. The private group aims to help children receive services they need to succeed.

General Colin Powell was chairman of America’s Promise Alliance when it was formed in 1997. He attended the press conference Tuesday where the report was released. He said studies have shown that the US must do more to educate the leaders and work force of the future.

Secretary of Education Margaret Spellings also spoke. She said the government will propose that states use the same methods when reporting graduation rates. Alliance officials also announced the start of a nationwide campaign to improve graduation rates. It is to include a series of meetings to be held in every state over the next two years. The meetings will bring together elected leaders, business owners, students, parents and education officials. They will develop plans to increase the number of Americans who finish high school.

小题1:The author wants to tell us ___________.

A.too many Americans do not finish high school

B.different methods to find graduation rates

C.services American children need to receive

D.the increase of the number of Americans who finish their high school小题2:From Paragraph 1 we can infer that __________.

A.there are 8,360,000 people in the US’ fifty largest cities

B.Wichita in Kansas is the smallest city in the US

C.50% of the people in the US don’t finish their high school education

D.high school graduation rates in or near the biggest cities are higher小题3: The underlined word “picture” probably can be replaced by “_______”.

A.situation

B.scene

C.image

D.mood小题4:From the last paragraph, we can draw a conclusion that _______-.

A.secretary of Education Margaret Spellings didn’t believe that number from the report

B.the government will stop using the cumulative promotion index to find graduation rates

C.secretary of Education Margaret Spellings announced the start of a nationwide campaign to improve graduation rates

D.the low graduation rates should be paid attention to by the government and the society

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