Didn't you observe the difference?是什么意思？

Didn't you observe the difference?

难道你没有看出差别?

you

pron. 你，你们，您们，各位，大家；

例句
I suggest you leave it to an expert...
我建议你把它留给专家来解决。

observe

vt.& vi. 观察，研究；vt. 遵守，观察，庆祝；vi. 注意，说，评述，当观察员；

例句
The Royal Greenwich Observatory was founded to observe and catalogue the stars.
当初创立皇家格林尼治天文台就是为了观察星体并对其进行编目。

the

art. 指已提到的人（物），指说话人与听者已知的人（物），用于独一无二的事物前，与形容词最高级和序数词连用；

例句
He did have a real knowledge of the country...
他对该国的确知之甚多。

difference

n. 差别，差异，[数]差数，差额，意见分歧，特色；vt. 辨别，区分；

例句
Contrary to popular belief, there is no evidence that what you look like makes much difference to your life.
和人们一般的看法相反，没有证据表明面相对人生有多大影响。