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.

一次物理考试 

        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。