历年托福考试阅读真题汇总包括答案.docx

历年托福考试阅读真题汇总包括答案
历年托福考试阅读真题汇总包括答案
1 / 16
历年托福考试阅读真题汇总包括答案
```
0308 托福试题
阅读（ 55minutes）
Question 1-11
If food is allowed to stand for some time, it putrefies .When the putrefied material
is examined microscopically ,it is found to be teeming with bacteria. Where do these
bacteria come from , since they are not seen in fresh food? Even until the mid-nineteenth
century, many people believed that such microorganisms originated by spontaneous
(5 ) generation ,a hypothetical process by which living organisms develop from nonliving
matter.
The most powerful opponent of the theory of spontaneous generation was the French chemist and microbiologist Louis Pasteur(1822-1895).Pasteur showed that structures
present in air closely resemble the microorganisms seen in putrefying materials .He did
this by passing air through guncotton filters, the fibers of which stop solid particles. After
the guncotton was dissolved in a mixture of alcohol and ether, the particles that it had
trapped fell to the bottom of the liquid and were examined on a microscope slide .Pasteur
found that in ordinary air these exists a variety of solid structures ranging in size from
mm to more than mm .Many of these bodies resembled the reproductive
structures of common molds, single-celled animals, and various
other microbial cells .
As many as 20 to 30 of them were found in fifteen liters of ordinary air ,and they could
not be distinguished from the organisms found in much larger numbers in putrefying materials .Pasteur concluded that the organisms found in putrefying materials originated
from the organized bodies present in the air .He postulated that
````
历年托福考试阅读真题汇总包括答案
历年托福考试阅读真题汇总包括答案
16 / 16
历年托福考试阅读真题汇总包括答案
```
these bodies are constantly
(20)being deposited on all objects.
Pasteur showed that if a nutrient solution was sealed in a glass flask and heated to
boiling to destroy all the li