托福考试写作必背范文：Scientific Theories

　　新托福考试写作考生想拿高分，“肚子里必须有点墨水”，背上一篇两篇优秀范文，以备不时只需。以下这篇范文的题目是：ScientificTheories。

　　In science, a theory is a reasonable explanation of observed events thatare related. A theory often involves an imaginary model that helps scientistspicture the way an observed event could be produced. A good example of this isfound in the kinetic molecular theory, in which gases are pictured as being madeup of many small particles that are in constant motion.

　　A useful theory, in addition to explaining past observations, helps topredict events that have not as yet been observed. After a theory has beenpublicized, scientists design experiments to test the theory. If observationsconfirm the scientist’s predictions, the theory is supported. If observations donot confirm the predictions, the scientists must search further. There may be afault in the experiment, or the theory may have to be revised or rejected.

　　Science involves imagination and creative thinking as well as collectinginformation and performing experiments. Facts by themselves are not science. Asthe mathematician Jules Henri Poincare said, “Science is built with facts justas a house is built with bricks, but a collection of facts cannot be calledscience any more than a pile of bricks can be called a house.”

　　Most scientists start an investigation by finding out what other scientistshave learned about a particular problem. After known facts have been gathered,the scientist comes to the part of the investigation that requires considerableimagination. Possible solutions to the problem are formulated. These possiblesolutions are called hypotheses.

　　In a way, any hypothesis is a leap into the unknown. It extends thescientist’s thinking beyond the known facts. The scientist plans experiments,performs calculations, and makes observations to test hypotheses. Withouthypothesis, further investigation lacks purpose and direction. When hypothesesare confirmed, they are incorporated into theories.

　　我们并不主张考生死记范文，考试时如果遇到类似题目照搬上去，这并不能考察考生的写作能力。新托福考试写作多背一些范文，可以积累一些素材，像好的短语、词、句等，灵活运用。