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。墨尔本文波雅思PTE培训学校专门为墨尔本，悉尼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：
Human Nose Tallies More Than a Trillion Scents
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。
A bloodhound’s sense of smell is far better than its owner’s. But human olfaction is still nothing to sneeze at. Because your nose can detect at least a trillion individual scents. That’s according to research in the journal Science. [C. Bushdid et al, Humans Can Discriminate More than One Trillion Olfactory Stimuli]
Researchers mixed together combinations of some of 128 different odors. Study subjects then smelled three samples: two of the combination scents that were the same and one that was different. Based on subjects’ id’s of the different smells, the researchers gauged how close the mixtures could be and still be distinguishable.
Those findings let them determine how many different scents could exist made of combinations of the original 128 odors. The result was more than a trillion.
Researcher Andreas Keller of The Rockefeller University told the journal Science’s podcast why humans have such a discerning sense of smell:
°∞Our olfactory system evolved°≠to discriminate very similar smells, like my baby from my neighbor’s baby, milk that’s still good from milk that turned bad. So those are very similar smells that only differ in a few components. So we evolved to be able to make those discriminations. And as a side effect of that we can discriminate all those other odors, too.°±