托福写作范文一直是考生们关注的，如果同学们能够用心的去学习借鉴一篇好的范文，你的托福写作水平肯定能够提升不少。本期为大家整理了这篇托福写作范文：Bacteria，供大家参考。
Bacteria are extremely small living things. While we measure our own sizes in inches or centimeters, bacterial size is measured in microns. One micron is a thousandth of a millimeter: a pinhead is about a millimeter across. Rod-shaped bacteria are usually from two to four microns long, while rounded ones are generally one micron in diameter. Thus if you enlarged a rounded bacterium a thousand times, it would be just about the size of a pinhead. An adult human magnified by the same amount would be over a mile (1.6 kilometer) tall.
Even with an ordinary microscope, you must look closely to see bacteria. Using a magnification of 100 times, one finds that bacteria are barely visible as tiny rods or dots. One cannot make out anything of their structure. Using special stains, one can see that some bacteria have attached to them wavy-looking “hairs” called flagella. Others have only one flagellum. The flagella rotate, pushing the bacteria through the water. Many bacteria lack flagella and cannot move about by their own power, while others can glide along over surfaces by some little- understood mechanism.
From the bacteria point of view, the world is a very different place from what it is to humans. To a bacterium water is as thick as molasses is to us. Bacteria are so small that they are influenced by the movements of the chemical molecules around them. Bacteria under the microscope, even those with no flagella, often bounce about in the water. This is because they collide with the watery molecules and are pushed this way and that. Molecules move so rapidly that within a tenth of a second the molecules round a bacteria have all been replaced by new ones; even bacteria without flagella are thus constantly exposed to a changing environment.
以上就是本期为大家推荐的托福写作范文，希望同学们在托福备考时能够认真的学习借鉴这篇写作范文的用词、用句、语法和段落的安排，促进自己的写作水平得到长足进步。若您想了解托福考试更多相关信息请关注百利天下出国考试。
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