虽然她错了，但这不是什么大事。

Although she's wrong, it's not a big deal.

这不是大事，别担心。

It's not a big deal, don't worry.

这次考试对我来说是个大事。

This exam is a big deal for me.

他们的婚礼是今年的大事。

Their wedding is the big deal of the year.

他总是把小事当成大事。

He always makes a big deal out of small things.