Once in a physics examination, Nick finished the first question very soon, while his classmates were thinking it hard. 

The question was: When it thunders why do we see the lighting first, then hear the thunderrolls? 

Nick's answer: Because our eyes are before ears.

在一次物理考试时，当同学们都还在苦思冥想时，尼克很快就答好了第一个问题。

这个问题是：为什么在打雷时，我们总是先看到闪电后听到雷声？

尼克的回答是：因为眼睛在前，耳朵在后。