『新东方在线托福阅读』为托福考生准备了ETS托福TPO/Official 57 Passage 2阅读练习：In paragraph 4, why does the author discuss Spallanzani's experiment of heating nutrient fluids after they were sealed in flasks?真题题目及答案解析，TPO/Official 57 Passage 2阅读原文范文音频翻译

托福TPO/Official 57 Passage 2阅读原文In paragraph 4, why does the author discuss Spallanzani's experiment of heating nutrient fluids after they were sealed in flasks?题目答案及解析-新东方托福官方网校手机版

直至19世纪下半叶，许多科学家和哲学家均认为，某些生命形式可以从无生命物质中自发产生; 他们把这个假设的过程称为无生源说。

Until the second half of the nineteenth century, many scientists and philosophers believed that some forms of life could arise spontaneously from nonliving matter; they called this hypothetical process spontaneous generation.

不到100年前，人们普遍认为蟾蜍、蛇和老鼠可以在潮湿的土壤中出生;苍蝇可以从粪便中滋生，而蛆虫，苍蝇的幼虫，可以从腐烂的尸体中滋生。

Not much more than 100years ago, people commonly believed that toads, snakes, and mice could be born of moist soil; that flies could emerge from manure, and that maggots, the larvae of flies, could arise from decaying corpses.

意大利医生弗朗切斯科•雷迪强烈反对无生源说，他从1668年开始证明蛆不是从腐烂的肉中自然产生。

A strong opponent of spontaneous generation, the Italian physician Francesco Redi, set out in 1668 to demonstrate that maggots did not arise spontaneously from decaying meat.

雷迪在三个罐子里装满了腐烂的肉，并把它们紧紧地密封起来。

Redi filled three jars with decaying meat and sealed them tightly.

然后，他又以类似的方式对另外三个罐子进行操作，但将它们打开。

Then he arranged three other jars similarly but left them open.

苍蝇进入罐子产卵后，蛆虫出现在敞开的容器中，但密封的容器中没有蛆虫的迹象。

Maggots appeared in the open vessels after flies entered the jars and laid their eggs, but the sealed containers showed no signs of maggots.

尽管如此，雷迪的反对者们并没有被说服; 他们声称新鲜空气是自然产生的必要条件。

Still, Redis antagonists were not convinced; they claimed that fresh air was needed for spontaneous generation.

因此，雷迪进行了第二次实验，用细网覆盖三个罐子来代替密封三个罐子。

So Redi set up a second experiment, in which three jars were covered with a fine net instead of being sealed.

尽管有空气，用网盖的罐子里没有出现幼虫。

No larvae appeared in the net-covered jars, even though air was present.

蛆只出现在苍蝇产过卵的肉上。

Maggots appeared only when flies were allowed to leave their eggs on the meat.

雷迪的研究结果对长期以来认为大量生命形式可以从非生命中产生的人们来说，是一个沉重的打击。

Redi's results were a serious blow to the long-held belief that large forms of life could arise from nonlife.

然而，很多科学家仍然认为，微小的微生物足够简单，可以从无生命的材料中产生。

However, many scientists still believed that tiny microorganisms were simple enough to be generated from nonliving materials.

1745年，微生物自发产生的观点似乎得到了加强，当时，英国人约翰·尼达姆发现，甚至将营养液(鸡汤和玉米汤)加热后再倒入盖着的烧瓶，冷却后的溶液很快就充满了微生物。

The case for spontaneous generation of microorganisms seemed to be strengthened in 1745, when John Needham, an Englishman, found that even after he heated nutrient fluids (chicken broth and corn broth) before pouring them into covered flasks, the cooled solutions were soon teeming with microorganisms.

尼达姆声称微生物是由这些液体自发产生的。

Needham claimed that microbes developed spontaneously from the fluids.

二十年后，意大利科学家Lazzaro Spallanzani提出，空气中的微生物可能是在尼达姆的溶液被煮沸后进入的。

Twenty years later, Lazzaro Spallanzani, an Italian scientist, suggested that microorganisms from the air probably had entered Needham's solutions after they were boiled.

Spallanzani表明，营养液先密封烧瓶中，之后再加热，其中就不会产生微生物。

Spallanzani showed that nutrient fluids heated after being sealed in a flask did not develop microbial growth.

Needham对此的回应是，自然生成所必需的“生命力”已经被热量破坏，并被密封圈挡在了烧瓶外。

Needham responded by claiming the "vital force" necessary for spontaneous generation had been destroyed by the heat and was kept out of the flasks by the seals.

在Spallanzani的实验之后不久，Laurent Lavoisier证明了氧气对生命的重要性，这种无形的“生命力”被更多人相信。

This intangible "vital force" was given all the more credence shortly after Spallanzani's experiment, when Laurent Lavoisier showed the importance of oxygen to life.

Spallanzani的言论受到了抨击，理由是密封瓶里没有足够的氧气来支持微生物的生命。

Spallanzani's observations were criticized on the grounds that there was not enough oxygen in the sealed flasks to support microbial life.

这个问题在1858年仍未解决，当时德国科学家Rudolf Virchow提出的生物起源论，即活细胞只能从预先存在的活细胞中产生，挑战了无生源论

The issue was still unresolved in 1858, when the German scientist Rudolf Virchow challenged spontaneous generation with the concept of biogenesis, the claim that living cells can arise only from preexisting living cells.

关于无生源论的争论一直到1861年法国科学家路易斯·巴斯德发表著作才得以结束。

Arguments about spontaneous generation continued until 1861, when the work of the French scientist Louis Pasteur ended the debate.

通过一系列巧妙而有说服力的实验，巴斯德证明了微生物存在于空气中，它们可以污染无菌溶液，但空气本身不会产生微生物。

With a series of ingenious and persuasive experiments, Pasteur demonstrated that microorganisms are present in the air and can contaminate sterile solutions, but air itself does not create microbes.

他在几个短颈烧瓶里装满了牛肉汤，然后将它们煮沸。

He filled several short-necked flasks with beef broth and then boiled their contents.

Some were then left open and allowed to cool.

几天后，这些敞开的烧瓶被微生物污染了。

In a few days, these flasks were found to be contaminated with microbes.

那些煮沸后密封的烧瓶中没有微生物。

The other flasks, sealed after boiling, were free of microorganisms.

根据这些结果，巴斯德推断空气中的微生物是污染非生命物质(如Needham烧瓶中的肉汤)的罪魁祸首。

From these results, Pasteur reasoned that microbes in the air were the agents responsible for contaminating nonliving matter such as the broths in Needham's flasks.

接着，巴斯德将肉汤放入开口长颈烧瓶中，并将烧瓶的颈部弯曲成s形。

Pasteur next placed broth in open-ended long-necked flasks and bent the necks into S-shaped curves.

然后，将烧瓶里的肉汤煮沸并冷却。

The contents of these flasks were then boiled and cooled.

结果甚至过了几个月，烧瓶里的肉汤也没有腐烂，更没有出现生命的迹象。

The broth in the flasks did not decay and showed no signs of life, even after months.

巴斯德独特的设计允许空气进入烧瓶，但弯曲的颈部截留了所有空气中可能污染肉汤的微生物。

Pasteur's unique design allowed air to pass into the flask, but the curved neck trapped any airborne microorganisms that might have contaminated the broth.

巴斯德表明，微生物能存在于非生命物质中——如固体、液体和空气中。

Pasteur showed that microorganisms can be present in nonliving matter-on solids, in liquids, and in the air.

他的实验提供了证据，证明微生物不能起源于非生命物质中存在的神秘力量。

His work provided evidence that microorganisms cannot originate from mysterious forces present in nonliving materials.

相反，在无生命溶液中任何“自发”生命的出现都可以归因于已经存在于空气或液体中的微生物。

Rather, any appearance of "spontaneous" life in nonliving solutions can be attributed to microorganisms that were already present in the air or in the fluids themselves.

The word "hypothetical" in the passage is closest in meaning to

According to paragraph 2, the purpose of Redi's second experiment was to show that spontaneous generation did not occur when

According to paragraph 3, how did Redi's experiments change the debate over spontaneous generation?

Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices change the meaning in important ways or leave out essential information.

In paragraph 4, why does the author discuss Spallanzani's experiment of heating nutrient fluids after they were sealed in flasks?

Paragraphs 6-8 suggest which of the following about the relationship between Pasteur's experiments and Virchow's concept of biogenesis?

According to paragraph 7, why did Pasteur think that the microorganisms that had contaminated the liquids in his experiment had come from the air?

According to paragraphs 7 and 8, Pasteur's experiment involving flasks with S-shaped necks proved that

Look at the four squares  that indicate where the following sentence could be added to the passage. This allowed air into the jars, but not flies.  Where would the sentence best fit? Click on a square  to add the sentence to the passage.

Directions: An introductory sentence for a brief summary of the passage is provided below. Complete the summary by selecting the THREE answer choices that express the most important ideas in the passage. Some sentences do not belong in the summary because they express ideas that are not presented in the passage or are minor ideas in the passage. This question is worth 2 points.

The Debate over Spontaneous Generation Until the second half of the nineteenth century, many scientists and philosophers believed that some forms of life could arise spontaneously from nonliving matter; they called this hypothetical process spontaneous generation. Not much more than 100 years ago, people commonly believed that toads, snakes, and mice could be born of moist soil; that flies could emerge from manure; and that maggots, the larvae of flies, could arise from decaying corpses. A strong opponent of spontaneous generation, the Italian physician Francesco Redi, set out in 1668 to demonstrate that maggots did not arise spontaneously from decaying meat. Redi filled three jars with decaying meat and sealed them tightly. Then he arranged three other jars similarly but left them open. Maggots appeared in the open vessels after flies entered the jars and laid their eggs, but the sealed containers showed no signs of maggots. Still, Redi’s antagonists were not convinced; they claimed that fresh air was needed for spontaneous generation. So Redi set up a second experiment, in which three jars were covered with a fine net instead of being sealed. No larvae appeared in the net-covered jars, even though air was present. Maggots appeared only when flies were allowed to leave their eggs on the meat. Redi’s results were a serious blow to the long-held belief that large forms of life could arise from nonlife. However, many scientists still believed that tiny microorganisms were simple enough to be generated from nonliving materials. The case for spontaneous generation of microorganisms seemed to be strengthened in 1745, when John Needham, an Englishman, found that even after he heated nutrient fluids (chicken broth and corn broth) before pouring them into covered flasks, the cooled solutions were soon teeming with microorganisms. Needham claimed that microbes developed spontaneously from the fluids. Twenty years later, Lazzaro Spallanzani, an Italian scientist, suggested that microorganisms from the air probably had entered Needham’s solutions after they were boiled. Spallanzani showed that nutrient fluids heated after being sealed in a flask did not develop microbial growth. Needham responded by claiming the “vital force” necessary for spontaneous generation had been destroyed by the heat and was kept out of the flasks by the seals. This intangible “vital force” was given all the more credence shortly after Spallanzani’s experiment, when Laurent Lavoisier showed the importance of oxygen to life. Spallanzani’s observations were criticized on the grounds that there was not enough oxygen in the sealed flasks to support microbial life. The issue was still unresolved in 1858, when the German scientist Rudolf Virchow challenged spontaneous generation with the concept of biogenesis, the claim that living cells can arise only from preexisting living cells. Arguments about spontaneous generation continued until 1861, when the work of the French scientist Louis Pasteur ended the debate. With a series of ingenious and persuasive experiments, Pasteur demonstrated that microorganisms are present in the air and can contaminate sterile solutions, but air itself does not create microbes. He filled several short-necked flasks with beef broth and then boiled their contents. Some were then left open and allowed to cool. In a few days, these flasks were found to be contaminated with microbes. The other flasks, sealed after boiling, were free of microorganisms. From these results, Pasteur reasoned that microbes in the air were the agents responsible for contaminating nonliving matter such as the broths in Needham’s flasks. Pasteur next placed broth in open-ended long-necked flasks and bent the necks into S-shaped curves. The contents of these flasks were then boiled and cooled. The broth in the flasks did not decay and showed no signs of life, even after months. Pasteur’s unique design allowed air to pass into the flask, but the curved neck trapped any airborne microorganisms that might have contaminated the broth. Pasteur showed that microorganisms can be present in nonliving matter—on solids, in liquids, and in the air. His work provided evidence that microorganisms cannot originate from mysterious forces present in nonliving materials. Rather, any appearance of “spontaneous” life in nonliving solutions can be attributed to microorganisms that were already present in the air or in the fluids themselves.