1994年Passage 4

"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 (胰腺).

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 (基因), 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. "

63. 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

[答案] D

[解題思路]

巴斯德的例子出現在文章第一段的最后一句話"He discovered the causes of many kinds of infections, but it was fifty or sixty years before cures were available"（他發現了許多傳染病的成因，但治療方法卻在五六十年后才問世），這句話主要服務于第一段前面兩句話的觀點"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"（我有極大的信心相信到這個十年期結束時我們將會詳盡地知曉癌細胞的生成原因，"微生物學家羅伯特·溫伯格，一位癌癥專家如此說道，"但是，"他又告誡說，"有些人認為一旦人們弄清了病因，治療方法很快就會跟上）。也就是說，發現癌癥的原因并不意味著癌癥很快就可以被治愈，因此正確答案為D選項。其他三個選項皆與第一段的主要觀點無關。

[題目譯文]

第一段中巴斯德的例子是用來             。
[A] 預測癌癥的秘密在10年內將被解開
[B] 暗示治療癌癥的前景是光明的
[C] 證明癌癥將在50-60年后可以被治愚
[D] 警告要征服癌癥還有很長一段路要走

64. 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

[答案] D

[解題思路]

本題可以與第二段進行一一對應并排除錯誤選項。A選項對應于該段第二句"In the year 2000, the National Cancer Institute estimates, that figure will be 75 percent"（據國家癌癥研究所，到2000年存活率將升至75％），但文章中沒有提到任何"drastic rise"，因此該選項錯誤。而B選項的表述也與這句話有出入，因為文章指的是今后五年的存活率為90%，而不是現在的情況。C選項的表述與該段最后兩句話"But other survival statistics are still discouraging-----13 percent for lung cancer, and 2 percent for cancer of the pancreas"（但其他類型癌癥的存活數據卻仍令人沮喪--肺癌13％，胰腺癌2％）的意思相反。D選項則很好地總結概括了全文的內容，是正確答案。

[題目譯文]

作者暗示到了2000年               。
[A] 皮膚癌患者在五年內生存下來的幾率會有很大的變化
[B] 現在90%的皮膚癌患者可以活到那個時候
[C] 各種癌癥患者生存下來的幾率都差不多
[D] 癌癥患者活下來的幾率不會有大的變化

65. 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

[答案] B

[解題思路]

本題對應于原文第三段的第二、三句話"The researchers made great progress in the early 1970s, when they discovered that oncogenes, which are cancer-causing genes (基因), are inactive in normal cells. Anything from cosmic rays to radiation to diet may activate a dormant oncogene, but how remains unknown"（研究人員在70年代早期取得了很大進展，他們發現導致癌癥的癌基因在正常細胞里是不活躍的。從宇宙射線、輻射到日常飲食，任何東西都可能激活一個處于靜止狀態的致癌基因，但如何激活的原因卻尚不為人知），即認為這種細胞只要沒有被激活都是無害的，因此正確答案為B選項。A和D選項都是這種細胞被激活以后才會出現的情況，而C選項與原文無關，屬無中生有。

[題目譯文]

癌基因是有                特征且可以引發癌癥的基因。
[A] 總是在一個健康人的身體中運行
[B] 只要沒有激活就是無害的
[C] 可以被從正常的細胞中趕出來
[D] 正常的細胞無法避開的