PTE考生目前最大的问题之一就是练习题缺乏。除了有限的基本官方书(PLUS,Testbuilder, OG)之外就没有题了。很多英语基础不是很扎实的同学很难找到练习材料。悉尼文波雅思PTE培训学校专门为澳洲,尤其是悉尼、墨尔本的PTE考生准备了适合PTE听力阅读练习的科学60秒。各位PTE同学可以练习PTE听力中的summarise spoken text和PTE口语中的retell lecture,PTE听力口语-科学60秒-Frosty Moss练习记笔记技巧和复述。废话少说,下面开始:
听力内容:
60秒科学节目(SSS)是科学美国人网站的一套广播栏目,英文名称:Scientific American – 60 Second Science,节目内容以科学报道为主,节目仅一分钟的时间,主要对当今的科学技术新发展作以简明、通俗的介绍,对于科学的发展如何影响人们的生活环境、健康状况及科学技术,提供了大量简明易懂的阐释。
This is Scientific American — 60-Second Science. I’m Christopher Intagliata.
Every spring, the Mississippi River dumps tens of thousands of tons of nutrient runoff into the Gulf of Mexico. Add temperature, current and wind to that pollution, and you have the Western Hemisphere’s largest stretch of oxygen-poor waters—a so-called “dead zone.”
That dead zone hits the Gulf’s famed—and financially important—brown shrimp fisheries. And it does two things: first, the low oxygen slows down the shrimps’ growth.
“The other thing that happens is what I like to call the burning building effect.” Martin Smith, an environmental economist at Duke University. “The shrimp try to avoid the low oxygen so they swim out of these areas of depleted oxygen. As a result they end up kind of aggregating on the edges. They kind of line up when they get outside the deoxygenated waters. And that’s why I call it the burning building effect. If you’re in a burning building you’re running to get out of the fire, you don’t keep running when you get outside, you stop and you take a breath.”
Fishermen flock to where those shrimp “take a breath.” And shrimp get caught earlier in the season. So combine these two effects—slower growth and earlier catches—and the result is a haul of more small shrimp, and fewer large and jumbo shrimp. Meaning the price on big shrimp temporarily goes up. Supply and demand, right?
Smith and his team studied that link—between the dead zone and a spike in large shrimp prices—using 20 years of shrimp pricing data. Their analysis is in the Proceedings of the National Academy of Sciences.
The brown shrimp fishery in the Gulf was once the most valuable in the U.S. Now, Smith says, we can measure the true cost of that nutrient runoff. “We can start to ask questions like, how much does the shrimp industry lose as a result of this problem, and how does that compare to what it would cost to control nutrient flows coming from food production upstream in the Mississippi watershed?” In other words—whether there might be some net economic benefit to keeping the water environmentally protected.
Thanks for listening for Scientific American — 60-Second Science Science. I’m Christopher Intagliata.
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