Don't talk the talk if you can't walk the walk. 不要光说不练，拿出实际行动。

talk the talk代表只会用嘴说

walk the walk可以理解成付诸于实际行动

这句话的意思就是：“不要耍嘴皮子，得去做才行。”

Let's see you do better.

这句话充满挑衅，带有戏谑的味道，“你这么厉害，肯定能做更好咯！”

除了以上的表达，还有一些“你行你上”的字面翻译：

If you're so good/clever/skilled, you do it!

既然你这么厉害，那你做呀！

If you're so good, why don't you do it?

既然你这么厉害，你咋不做呢？

If you're such an expert, why aren't you doing it?

既然你是专家，怎么没看你做呢？