Hang on to something

To hang on to something is to keep something.

I wouldn’t advice selling that property. You should hang on to it – its value will appreciate.
I am glad that I hung on to that painting. They are now offering millions for it.
I can’t believe that you sold your shares for such a low price. You should have hung on to them.

Fair Enough
Fair enough is something you say to show that you understand why someone has done or said something.

‘I was very annoyed with him and that’s why I hit him.’ ‘Fair enough.’ (I understand why you hit him.)
‘You will not watch TV if you do not finish your homework.’ ‘Fair enough.’

Cat Got Your Tongue

Cat got your tongue? = You have nothing to say?

‘What happened? You always have an opinion. Cat got your tongue?’
‘Cat must have got her tongue. She is unusually silent today.’

It’s a Deal

It’s a deal is something you say when you agree to a proposal.

‘So you will give me that painting, if I give you 50 dollars?’ ‘It’s a deal!’
‘If I stop eating hamburgers, I will not have to jog every day?’ ‘It’s a deal!’
‘If you water my plants, I will buy you an ice-cream.’ ‘Sounds good. It’s a deal!’