英語(yǔ)四級(jí)基礎(chǔ)閱讀訓(xùn)練 Text 30

Text 30

I have great confidence that by the end of the decade we'll know in vast detail how cancer cells arise, says microbiologist Robert Weinberg, an expert on cancer. "But," he cautions, "some people have the idea that once one understands the causes, the cure will rapidly follow. Consider Pasteur, he discovered the causes of many kinds of infections, but it was fifty or sixty years before cures were available."

This year, 50 percent of the 910,000 people who suffer from cancer will survive at least five years. In the year 2000, the National Cancer Institute estimates, that figure will be 75 percent. For some skin cancers, the five-year survival rate is as high as 90 percent. But other survival statistics are still discouraging — 13 percent for lung cancer, and 2 percent for cancer of the pancreas.

With as many as 120 varieties in existence, discovering how cancer works is not easy. The researchers made great progress in the early 1970s, when they discovered that oncogenes, which are cancer-causing genes, are inactive in normal cells. Anything from cosmic rays to radiation to diet may activate a dormant oncogene, but how remains unknown. If several oncogenes are driven into action, the cell, unable to turn them off, becomes cancerous.

The exact mechanisms involved are still mysterious, but the likelihood that many cancers are initiated at the level of genes suggests that we will never prevent all cancers. "Changes are a normal part of the evolutionary process," says oncologist William Haywar. Environmental factors can never be totally eliminated; as Hayward points out, "We can't prepare a medicine against cosmic rays."

The prospects for cure, though still distant, are brighter.

First, we need to understand how the normal cell controls itself. Second, we have to determine whether there are a limited number of genes in cells which are always responsible for at least part of the trouble. If we can understand how cancer works, we can counteract its action.

1.The example of Pasteur in the passage is used to_______.

A.predict that the secret of cancer will be disclosed in a decade

B.indicate that the prospects for curing cancer are bright

C.prove that cancer will be cured in fifty to sixty years

D.warn that there is still a long way to go before cancer can be conquered

2.The author implies that by the year 2000,_______.

A.there will be a drastic rise in the five-year survival rate of skin-cancer patients

B.90 percent of the skin-cancer patients today will still be living

C.the survival statistics will be fairly even among patients with various cancers

D.there won't be a drastic increase of survival rate of all cancer patients

3.Oncogenes are cancer-causing genes_______.

A.that are always in operation in a healthy person

B.which remain unharmful so long as they are not activated

C.that can be driven out of normal cells

D.which normal cells can't turn off

4.The word "dormant" in the third paragraph most probably means_______.

A.dead　　B.ever-present　　C.inactive　　D.potential

5.It can be inferred that the severity of cancers can be ranked as_________.

A.skin cancer, lung cancer, pancreas cancer　　B.skin cancer, Pancreas cancer, lung cancer

C.lung cancer, skin cancer, pancreas cancer　　D.pancreas cancer, skin cancer, lung cancer

長(zhǎng)難例句分析

［長(zhǎng)難例句］The researchers made great progress in the early 1970s, when they discovered that oncogenes, which are cancer-causing genes, are inactive in normal cells.

［結(jié)構(gòu)分析］本句中，主干是The researchers made great progress。when引導(dǎo)的是非限定性定語(yǔ)從句，修飾前面的時(shí)間。在這個(gè)定語(yǔ)從句中， that...cells是賓語(yǔ)從句，其中which are cancer-causing genes為非限定性定語(yǔ)從句，修飾oncogenes。

［參考譯文］在20世紀(jì)70年代初，研究者們?nèi)〉昧酥卮筮M(jìn)展，那時(shí)他們發(fā)現(xiàn)在普通細(xì)胞中，致癌基因并不活躍。

全文參考譯文

“我深信，在本年代末，我們將對(duì)癌細(xì)胞的產(chǎn)生有更詳細(xì)的了解?！蔽⑸飳W(xué)家及癌癥專(zhuān)家Robert Weinberg說(shuō)?！暗?，”他警告說(shuō)，“有些人認(rèn)為，一旦人們找到了病因，就會(huì)很快找到治療辦法。想一想Pasteur，他發(fā)現(xiàn)了許多傳染病的起因，但是五六十年后才出現(xiàn)了治療方法?！?/p>

今年，91萬(wàn)癌癥患者中，50％的人至少可生存5年。國(guó)家癌癥研究所估計(jì)，到2000年，這個(gè)數(shù)字將會(huì)是75％。對(duì)于一些皮膚癌患者，5年的生存率高達(dá)90％。但是其他生存統(tǒng)計(jì)數(shù)字仍令人失望——肺癌患者13％，胰腺癌患者2％。

由于存在著120多種不同的癌癥，發(fā)現(xiàn)癌癥的機(jī)理并不容易。在20世紀(jì)70年代初，研究者們?nèi)〉昧酥卮筮M(jìn)展，那時(shí)他們發(fā)現(xiàn)在普通細(xì)胞中，致癌基因并不活躍。從宇宙射線輻射到飲食的任何東西都可能激活處于休眠狀態(tài)的致癌基因，但如何維持這種狀態(tài)還不為人知。如果一些致癌基因被激活，而細(xì)胞不能消滅它們，細(xì)胞就變成癌細(xì)胞。

包含其中的準(zhǔn)確機(jī)理仍然是一個(gè)未知數(shù)。但是許多癌癥起因于基因這一可能性，表明我們永遠(yuǎn)不能預(yù)防所有的癌癥?！白兓沁M(jìn)化過(guò)程的正常組成部分，”腫瘤學(xué)家William Haywar說(shuō)。環(huán)境因素永遠(yuǎn)不可完全排除在外；正如他指出的那樣，“我們無(wú)法準(zhǔn)備一種對(duì)付宇宙射線的藥物?！?/p>

治療前景雖然還很遙遠(yuǎn)，但越加光明起來(lái)。

“首先，我們需要知道普通細(xì)胞是如何控制自己的。其次，我們必須確定細(xì)胞中是否有有限數(shù)量的基因經(jīng)常成為癌癥的起因或至少部分起因。如果我們知道了癌癥發(fā)作機(jī)理，我們就能采取相應(yīng)的措施?！?/p>

題目答案與解析

1.文中舉用Pasteur的例子，是用來(lái)_________。

A.預(yù)言10年后癌癥的秘密將被揭開(kāi)　　B.預(yù)示治療癌癥的前景是光明的

C.證明50～60年后癌癥將被治愈　　　D.告誡在征服癌癥之前還有很長(zhǎng)的路要走

【答案】D

【解析】從第一段最后一句“想一想Pasteur吧，他發(fā)現(xiàn)了許多傳染病病因，但是過(guò)了五六十年才有了治療方法”，可知D項(xiàng)為正確答案。

2.作者暗示到2000年，______。

A.5年生存率的皮膚癌患者會(huì)有大幅度的增加

B.今天90％的皮膚癌病人仍然活著

C.各種癌癥患者之間的生存率統(tǒng)計(jì)數(shù)字將會(huì)持平

D.所有癌癥患者生存率不會(huì)有大的提高

【答案】D

【解析】本題為推斷題。A、B、C項(xiàng)均不正確。D項(xiàng)正確。

3.致癌基因就是引起癌癥的基因，它們_________。

A.總是活躍在健康人體內(nèi)　　　　　B.只要不被激活，就不會(huì)有害

C.可以從正常細(xì)胞中驅(qū)趕出去　　　D.正常細(xì)胞無(wú)法排除

【答案】B

【解析】從第三段第二句意為：“20世紀(jì)70年代初，研究者們?nèi)〉昧撕艽筮M(jìn)步，當(dāng)時(shí)他們發(fā)現(xiàn)在正常細(xì)胞中，致癌基因并不活躍。從宇宙射線到輻射飲食等任何東西都可能激活休眠的致癌基因，但這一過(guò)程仍然不為人知。如果幾個(gè)致癌基因被激活，而細(xì)胞不能將他們消滅，則會(huì)成為癌細(xì)胞?！睆闹锌芍狟項(xiàng)為正確答案。

4.第三段中的單詞“dormant”最有可能意味著_________。

A.死的　　B.經(jīng)常存在的　　C.不活動(dòng)的　　D.潛在的

【答案】C

【解析】dormant：adj. 睡眠狀態(tài)的，靜止的，隱匿的。inactive：adj. 無(wú)行動(dòng)的，不活動(dòng)的，停止的，怠惰的，非活動(dòng)的?？芍鸢笧镃項(xiàng)。

5.按照嚴(yán)重性程度，可以推理出癌癥的順序?yàn)開(kāi)________。

A.皮膚癌，胰腺癌，肺癌　　B.皮膚癌，肺癌，胰腺癌

C.肺癌，皮膚癌，胰腺癌　　D.胰腺癌，肺癌，皮膚癌

【答案】D

【解析】從活過(guò)5年的癌癥患者的比例來(lái)看，分別是皮膚癌90％，肺癌13％和胰腺癌2％，由此可以推理出來(lái)其嚴(yán)重程度。