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 Karen Hopkin.
Got a minute?
I don’t believe, in all my years, I have ever seen a fruit fly I would consider obese. But, thanks to the wonders of modern science, that’s all about to change. Because a team of researchers from Cold Spring Harbor laboratory has produced the first flies that are genetically engineered to overeat.
If you are wondering…why…it’s not as silly as it might sound. A big part of weight control has to do with making healthy dietary choices and knowing when to step away from the snack cabinet. But what controls those behaviors?
Well, we humans have a hormone called leptin that tells us that we’re full. After eating, leptin is released from our fat cells. And it travels to our brains to signal that we’ve had enough. Indeed, people who don’t produce leptin…or who lack the molecular machinery to detect it…really pack on the pounds.
In the new study, researchers discovered a hormone that acts the same way in flies. And when they deleted the gene that encodes it, the hormonally deficient insects just kept eating. And when presented with the fly equivalent of a high-fat or high-sugar diet, they gained three times more weight than did their hormonally competent peers. The findings appear in the journal Cell Metabolism.
Interestingly, giving human leptin to these tubby bugs eliminates their tendency to binge. That suggests that by studying these flies, scientists might learn something that’s relevant to us.
In the meantime, researchers from the U.K. and Australia have also been plying flies with sweet treats. And they found that consuming large amounts of sugar may lead to fewer birthday cakes.
In this study, researchers compared the life spans of flies that ate a healthy diet, with 5 percent sugar…to those that went on a three-week bender of 40 percent sucrose. That’s the equivalent, the researchers note, of a person who really took Marie Antoinette’s advice to heart and ate only cake for two decades.
The results? The sugar-fed flies lost about 7 percent of their already brief 90-day life span. And that was even if they reverted to the healthy diet after their three weeks on sweets. These results appear in the journal Cell Reports.
The sugar overload apparently triggered long-term changes in gene activity…which accelerated aging and had the sugar-buzzed flies dropping like, well, like flies.
The findings suggest that you can have your cake and eat it, too. But not for long.
Thanks for listening for Scientific American — 60-Second Science Science. I’m Karen Hopkin.
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