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:
听力内容:
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It’s a scenario straight out of Hollywood:
You’re up in a spacecraft, “you’ve got this capsule around you,” and a loose bolt, a piece of space junk, is zooming your way.
“And it’s going really fast.
It’s going to very likely pass through your spacecraft and leave both entry and exit holes.
So all of a sudden now your atmosphere is rushing out those holes, and you want them sealedright away.”
That’s Timothy Scott, a polymer scientist at the University of Michigan, Ann Arbor.
He and his team have devised a potential solution to this space disaster:a material thatpatches itself up, less than a second after impact.
Think of an ice–cream sandwich.
“The central part, the ice cream of our sandwich, is a liquid resin.”The cookie parts are sheetsof thermoplastic.
When a projectile—or piece of space junk—punctures the sandwich,it exposes the liquid partto the ship’s oxygen, which causes it to solidify, patching the hole.
The researchers tested sheets of the self–healing material at a firing range, filming the resultswith high–speed video.
And indeed, the material worked fine here on Earth,but they say the findings will have to bereplicated under pressure conditions like those you’d find in space.
The results are in the journal ACS Macro Letters.
The space station is already well protected by bumpers that vaporize particles on impact.
But protection doesn’t come cheap.
“It turns out that robust things are also very heavy.
The intent of this is really to provide a backup that’s very low weight.”
It costs some 10,000 a pound to launch equipment into space today.
So a lighter weight material could save money—and lives.