托福阅读解析之一：为什么要关注例子前面的一句话

一般写作中，通常先阐明一个道理或论证对象，然后举例证明这个道理或论证对象，所以例子前面的一句话通常是论证对象。

接下来，通过TPO 13–Biological Clocks中的一道修辞目的题来说明，为什么要关注例子前面的一句话?

例题1

Survival and successful reproduction usually require the activities of animals to be coordinated with predictable events around them. Consequently, the timing and rhythms of biological functions must closely match periodic events like the solar day, the tides, the lunar cycle, and the seasons. The relations between animal activity and these periods, particularly for the daily rhythms, have been of such interest and importance that a huge amount of work has been done on them and the special research field of chronobiology has emerged. Normally, the constantly changing levels of an animal's activity—sleeping, feeding, moving, reproducing, metabolizing, and producing enzymes and hormones, for example—are well coordinated with environmental rhythms, but the key question is whether the animal's schedule is driven by external cues, such as sunrise or sunset, or is instead dependent somehow on internal timers that themselves generate the observed biological rhythms. Almost universally, biologists accept the idea that all eukaryotes (a category that includes most organisms except bacteria and certain algae) have internal clocks. By isolating organisms completely from external periodic cues, biologists learned that organisms have internal clocks. For instance, apparently normal daily periods of biological activity were maintained for about a week by the fungus Neurospora when it was intentionally isolated from all geophysical timing cues while orbiting in a space shuttle. The continuation of biological rhythms in an organism without external cues attests to its having an internal clock. (TPO 13：Biological Clocks)

In the paragraph, the experiment on the fungus Neurospora is mentioned to illustrate

existence of weekly periods of activity as well as daily ones

finding of evidence that organisms have internal clocks

effect of space on the internal clocks of organisms

isolation of one part of an organism's cycle for study

讲解：

通过分析题干(真菌试验用于阐明什么?)，我们知道这道题目属于修辞目的题。

首先，根据题干所给细节(例子)，即真菌试验，去原文段落中定位(见标红部分)，并将细节所在的那句话读懂(见染黄部分)。染黄部分是一个真菌试验的例子，当真菌在太空飞船中绕轨飞行时，不受地球引力影响，完全处于真空中，科学家发现真菌的日常生物钟能够维持一周。在读懂这个例子之后，同学们肯定会疑问，作者为什么要用这个例子?作者想用这个例子想阐明什么观点?

接下来，我们去例子前面看一看(见染蓝部分)，作者究竟想用这个例子阐明什么。我们通过染蓝部分发现，作者想表达隔离生物体与外部时间线索，生物学家可以发现生物体拥有内部生物种。

综上所述，通过真菌在太空进行试验的例子，生物学家可以发现生物体的内部生物钟。

答案：B

本文作者：考情报告(微信公众号：纯青教育)