湖南龙网

  1. 首页 > 生活百科 > >

托福听力双选题多少分 托福听力2大重听题型细节介绍( 二 )

生活百科托福听力


演讲听写训练 2
This coffee can contains soil from my garden. And I prepared slide samples to show you that it is alive. This ordinary backyard dirt is crawling with microbes. Microbes is not a very specific term. There are hundreds of thousands of different species called microbes. What they have in common is that we can't see them with a naked eye. They are microscopic. Look at this slide. You should see some round cells. Those are yeasts . Yeasts are fermenters. And they are necessary for making bread, beer, yogurt and so forth. Now look for an irregular shape with hairs coming out of it. That's a mold. Molds are decomposers, and they are responsible for the decomposition mycoplastlees. You should also see some protozoa. Some protozoa, like the one causes malaria are harmful to people. A microbic that causes disease is called a pathogen. Finally you should see a lot of squiggly lines. They are bacteria. The oldest form of life on earth. Like these other microbes, bacteria are single-cells. But they are even simpler structurally because their cells do not have nuclear. So I've got about a teaspoon of soil in my hand here. In that teaspoon are about ten thousand protozoa, 200 thousand mold cells, a million yeasts, and probably a billion bacteria.
演讲听写训练 3
Ten years ago the eccentric cyclist peddling furiously through the first snowstorm of the year was a rare sight often captured on film for the evening news? Today however it is estimated that four to five percent of cyclists bicycle year round. The increased popularity of winter cycling can be attributed to the creation of mountain bike and its subsequent imitations. Outfitted with parts more sturdy than those of yesterday, equipped with their more stable bicycles, nothing seems to stop the new breed of winter cyclist. With streets dry and clear on most winter days, many winter cyclists wear running shoes and protect themselves from cold by wearing down-hill-skiing clothes. On wet days cyclists can wear special water-proof boots over their shoes. But for all of its popularity, there is a down side to winter cycling. Even mountain bikes can't withstand winter snow and rain without extensive upkeep. But one bicycle store owner is in the final stages of developing a year-round bicycle with an innovated complete chain cover. With bicycle chains covered, cyclists would need to clean and oil their chains only once every six months instead of once a week. Despite her invention, however, she still advises cyclists to take a taxi or bus when it snowing heavily. Not because the conditions are too arduous for bicycles but because she believes bikers can't have confidence in the people who drive cars on days of reduced visibility.
托福听力每日一练lecture原文
演讲听写训练1
In the early 1800s, the paper industry was still using rags as its basic source of fiber as it had for many centuries. However the rag supply couldn't keep up with the growing demand for paper. The United States alone was using 250 thousand tons of rags each year. And a quarter of that had to be imported. It was clear that a new source of fiber was needed to keep up with the demand for paper. The answer to this problem turned out to be paper made from wood pulp, something that was abundantly available in north America. In Canada, the first wood pulp mill was set up in 1866 and it was immediately successful. But while wood pulp solved the problem of quantity it created a problem of quality. Wood contains a substance called lignin. The simplest way to make large quantities of cheap paper involves leaving the lignin in the wood pulp. But lignin is acidic and its presence in paper has shorten the life expectancy of paper from several centuries for rag paper to less than a century for paper made from wood pulp. This means that books printed less than a hundred years ago are already turning yellow and beginning to disintegrate, even though books printed much earlier maybe in fine condition. This is bad enough for the older books on your bookshelf but it poses a huge problem for libraries and the collections of government documents.

推荐阅读


上一篇：1千克是多少斤 体重

下一篇：自测皮肤色调 教你如何选择彩妆产品