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：
Bioexplorers Find Tongue’s Taste Bud Factory
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。
Taste may be the least understood of our five senses. Even basic questions, like where do taste buds come from, remained mysterious. Until now. In a study published in the journal Stem Cell, scientists have identified the elusive “parental” cell that give rise to the daughter cells responsible for taste. [Karen K. Yee et al., Lgr5-EGFP Marks Taste Bud Stem/Progenitor Cells in Posterior Tongue]
Taste buds are made of clusters of taste cells, which contain the receptors for sweet, salty, sour, bitter and umami. They’re concentrated in the bumpy papillae that cover the tongue’s surface. But taste buds are not static structures. Their resident taste cells live only about two weeks before being replaced by newborn baby taste cells. After all, a pizza burn is not permanent. But no one knew the address of the taste cell nursery.
To track it down, scientists scanned the tongue for cells that produce the same marker protein as the body’s other stem cells, which give rise to our other specialized cells. The researchers discovered a reservoir of stem cells that line the trenches around the papillae at the back of the tongue.
These stem cells can produce all of the different taste cell types, and so allow us to savor all of life’s flavors.
—Karen Hopkin
