文档介绍：
老托福阅读真题 PASSAGE 99
托福阅读的思维方式就是托福阅读的出题方式，只有掌握了这种思维方式，才有可能在做题之
前，预测到新托福阅读题的出题形式和特点，为找答案节省时间。老托福阅读试题的核心价值，在
于其最贴近真题的阅读思维方式。此外老托福阅读真题比新托福 IBT 阅读文章要短，比较容易适应。
这也是大家在备考托福的时候非常重要的一点。因为前期的入手如果能从容易的开始，就会形成一
个循序渐进的过程方式，让大家的练****有一个提高的过程。
既然老托福阅读试题有这样的效果，那我们如何利用那有限的真题来达到锻炼自己的目的呢?
事实上这就一个办法，就是坚持。本期为大家推荐老托福阅读的真题 PASSAGE 99，有原文及答案，
希望对托福考生备考有所帮助。
Scientists have discovered that for the last 160,000 years, at least, there has been a
consistent relationship between the amount of carbon dioxide in the air and the average
temperature of the planet. The importance of carbon dioxide in regulating the Earth's
temperature was confirmed by scientists working in eastern Antarctica. Drilling down into a
glacier, they extracted a mile-long cylinder of ice from the hole. The glacier had formed as
layer upon layer of snow accumulated year after year. Thus drilling into the ice was
tantamount to drilling back through time.
The deepest sections of the core are composed of water that fell as snow 160,000 years
ago. Scientists in Grenoble, France, fractured portions of the core and measured the
composition of ancient air released from bubbles in the ice. Instruments were used to
measure the ratio of certain isotopes in the