There's nothing to it. 很简单

A: Oh man！You're really good at picking up girls.

天呐！你真的很会泡妞。

B: There's nothing to it. I am just rich and handsome.

很简单啊。我只是有钱，比较帅而已。

demanding 费时费力的

Police work is physically demanding and stressful.

警察的工作考验体力，压力大。

challenging 有难度的，考验人的

You find out what you are capable of when you are in a really challenging situation.

当你身处一个真正考验人的境地中的时候，你会发现自己到底擅长什么。

tough 困难的；棘手的

It's a tough time for us at the moment so we must stick together.

现在对我们来说是困难时期，我们必须团结在一起。

Easier said than done.

说着容易做着难