Don't waste your breath trying to persuade him.

别白费唇舌去说服他了。

With open arms:

张开手臂 ×

热烈欢迎 √

例句：

Let's welcome Mr. Green with open arms.

让我们热烈欢迎格林先生的到来。

A pair of hands:

①一双手

②一个能做事的人

例句：

Colleagues regard him as a safe pair of hands.

同事们都认为他干事可靠。

Take things as they come:

当他们来，我们就拿走×

随遇而安 √

例句：

Don't get depressed when facing problems. Just take things as they come.

面临困难时，不必消沉。只要一一解决目前的问题就行。