托福阅读考试真题9Word格式文档下载.docx

1、bacteria come from , since they are not seen in fresh food? Even until the mid-nineteenthcentury, many people believed that such microorganisms originated by spontaneous（5 ） generation ,a hypothetical process by which living organisms develop from nonlivingmatter.The most powerful opponent of the th

2、eory of spontaneous generation was the French chemist and microbiologist Louis Pasteur（1822-1895）.Pasteur showed that structurespresent in air closely resemble the microorganisms seen in putrefying materials .He did（10）this by passing air through guncotton filters, the fibers of which stop solid par

3、ticles. Afterthe guncotton was dissolved in a mixture of alcohol and ether, the particles that it hadtrapped fell to the bottom of the liquid and were examined on a microscope slide .Pasteurfound that in ordinary air these exists a variety of solid structures ranging in size from0.01 mm to more than

4、 1.0 mm .Many of these bodies resembled the reproductive（15）structures of common molds, single-celled animals, and variousother microbial cells .As many as 20 to 30 of them were found in fifteen liters of ordinary air ,and they couldnot be distinguished from the organisms found in much larger number

5、s in putrefying materials .Pasteur concluded that the organisms found in putrefying materials originatedfrom the organized bodies present in the air .He postulated that1these bodies are constantly（20）being deposited on all objects.Pasteur showed that if a nutrient solution was sealed in a glass flas

6、k and heated toboiling to destroy all the living organisms contaminating it, it never putrefied .The proponents of spontaneous generation declared that fresh air was necessary forspontaneous generation and that the air inside the sealed flask was affected in some way（25）by heating so that it would n

7、o longer support spontaneous generation. Pasteur constructed a swan-necked flask in which putrefying materials could he heated to boiling, but aircould reenter. The bends in the neck prevented microorganisms from getting in the flask. Material sterilized in such a flask did not putrefy.1,What does t

8、he passage mainly discuss?（a）Pasteur s influence on the development of the microscope.（b）The origin of the theory of spontaneous generation .（c）The effects of pasteurization on food.（d）Pasteur s argumentnstagaithe theory of spontaneous generation .2,The phrase “ teeming with ” in line 2 is closest i

9、n meaning to （a）full of（b）developing into（c）resistant to（d）hurt by3,Which of the following questions did the theory of spontaneous generation attempt to answer?（a）What is the origin of the living organisms are seen on some food?（b）How many types of organisms can be found on food?（c）What is the most

10、effective way to prepare living organisms for microscopic examination?（d）How long can food stand before it putrefies?4,The word “ resemble ” in line 9 is closest in meaning to（a）benefit from（b）appear similar to2（c）join together with（d）grow from5,The purpose of the “ guncotton ” mentioned in paragrap

11、h 2 was to （a）trap particles for analysis（b）slow the process of putrefaction （c）increase the airflow to the microscopic slide （d）aid the mixing of alcohol and ether6,The author mention “ 1.0mm” in line 14 in describing the （a）thickness of a layer of organisms that was deposited on an object （b）diame

12、ter of the fibers that were in the guncotton filters （c）thickness of the microscope slides that were used（d）size of the particles that that were collected7.The word “ postulated ” in line 19 is closest in meaning to （a）analyzed（b）doubted（c）persuaded（d）suggested8.The objects that Pasteut removed from

13、 the air in his experiment were remarkable because they were（a）primarily single-celled organisms（b）no different from objects found in putrefying materials （c）fairly rare（d）able to live in a mixture of alcohol and ether9.The word “ it ” in line 22 refers to（a）a nutrient solution（b）a glass flask（c）boi

14、ling（d）spontaneous generation10.According to paragraph 3,proponents of spontaneous generation believed that which of the following was important for the process to succeed ?（a）A sealed container（b）Fresh air3（c）Heat（d）The presence of nutrients11.It can be inferred from paragraph 3 that Pasteur employ

15、ed a swam-necked flask to（a）store sterilized liquids for use in future experiments （b）prevent heat from building up in a solution （c）disprove a criticism of his conclusions （d）estimate the number of organisms in a liter of airQuestions 12-20In the early decades of the United States ,the agrarian movement promoted the farmeras society heros. In the minds of