These are special phrases that English speakers use all the time, but you don't often see these phrases in English course books or other study material.
They can be used in spoken or written communication formally or informally.
“I'll get back to you”
We use this expression to say that we need to find some information or do something and will contact the person later.SpokenWrittenInformalExample 1Can you tell me how many students are taking the exam next month?
I'll find out.
I'll get back to you.
Example 2Do you know what has been decided?
Not yet.
I'll get back to you on that.
“Keep it up”
We use this expression to encourage someone to continue doing something we think is good. Spoken Formal Written InformalExample 1I've been working hard. I think I'm making progress.
Great.
Keep it up.
Example 2Is this the right way to do it?
Yes, that's it.
Keep it up.
“I could do with a ...”
We use this expression to say that we really want or need something. Spoken Formal Written InformalExample 1You've had a really hard day.
Yes,
I could do with a drink!
Example 2You look exhausted.
Yes,
I could do with a good night's sleep.
“Suppose”
We use this expression to introduce a question about a possibility, real or unlikely. It is like asking 'what if?' or 'imagine' Spoken InformalExample 1Suppose you had a million dollars - what would you do?
I think I'd buy a house in the Bahamas.
Example 2You took Jack's last sandwich?
Suppose he finds out?
He won't. I'm not going to tell him.
“You should know”
We use this expression to say that we think someone logically should have the information needed in a specific situation. Spoken InformalExample 1How do you say 'be quiet' in Spanish?
You should know - you lived in Spain for 6 months.
Example 2What time did the party finish last night?
You should know - you were the last person to leave!