It took a practised eye to spot the difference.

　　只有內行人才能看出其中的差異。

　　Can you spot the difference between these two pictures?

　　你能不能看出這兩幅畫(huà)有什么不同？

　　Nothing I do makes any difference anyway, so why bother?

　　不管我做什么都沒(méi)有區別，那為什么還要費心去做呢？