Passage 3
h2G$@8t}I In science, a theory is a reasonable explanation of observed events that are related. A the-ory often involves an imaginary model that helps scientists picture the way an observed event could be produced. A good example of this is found in the kinetic molecular theory, in which gases are pictured as being made up of many small particles that are in constant motion.
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Q> A useful theory, in addition to explaining past observations, helps to predict events that have not as yet been observed. After a theory has been publicized, scientists design experi-merits to test the theory. If observations confirm the scientists’ predictions, the theory is sup-ported. If observations do not confirm the predictions, the scientists must search further. There may be a fault in the experiment, or the theory may have to be revised or rejected.
_852H$H\ Science involves imagination and creative thinking as well as collecting information and performing experiments. Facts by themselves are not science. As the mathematician Jules Henri Poincare said: "Science is built with facts just as a house is built with bricks, but a collection of facts cannot be called science any more than a pile of bricks can be called a house." Most scientists start an investigation by finding out what other scientists have learned about a particular problem. After known facts have been gathered, the scientist comes to the part of the investigation that requires considerable imagination. Possible solutions to the problem are
fp`;U_-&0 formulated. These possible solutions are called hypotheses.
+S o4rA*9 In a way, any hypothesis is a leap into the unknown. It extends the scientist’s thinking beyond the known facts. The scientist plans experiments, performs calculations, and makes ob-servations to test hypotheses. For without hypotheses, further investigation lacks purpose and direction. When hypotheses are confirmed, they are incorporated into theories.
6^]+[q}3 11. The word "this" in the 3rd sentence in paragraph 1 refers to ______.
T&6l$1J A) a good example B) an imaginary model
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U?. C) the kinetic molecular theory D) an observed event
~%<X0s| 12. Bricks are mentioned in the 3rd paragraph to indicate how ____.
H\ F:95 A) mathematicians approach science
m|n B) building a house is like performing experiments
ua3~iQj- C) science is more than a collection of facts
*/`ki;\A D) scientific experiments have led to improved technology
01t1Z}!y 13. In the last paragraph, the author refers to a hypothesis as "a leap into the unknown" in or- der to show that hypotheses ______.
h4fJvOk|! A) are sometimes ill-conceived B) can lead to dangerous results
-r`.#c4 C) go beyond available facts D) require effort to formulate
5_GYrR2 14. What is a major function of hypotheses as implied in the last paragraph7
3lrT3a3vV A) Sifting through known facts.
Ag-(5: B) Communicating a scientist’s thoughts to others.
fK>L!=Q C) Providing direction for scientific research.
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1E-4 D) Linking together different theories.
0q()|y?} 15. Which of the following statements is supported by the passage?
!|S(Ms A) Theories are simply imaginary models of past events.
L+b6!2O, B) It is better to revise a hypothesis than to reject it.
G/)O@Ugp C) A scientist’s most difficult task is testing hypotheses.
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d D) A good scientist needs to be creative.
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5'OrHk;u Passage 3
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