I have long wanted to be a teacher because I think it is a very noble cause.

我一直想成为一名老师，因为我认为这是非常崇高的事业。

He died for a noble cause.

他为了高尚的事业而牺牲。

You've helped a noble cause.

你在从事一项高尚的事业。

What noble cause do you believe in?

你信仰哪种神圣的事业？

He devoted himself to a noble cause.

他献身于一项崇高的事业。