Different ways to say 'I don't know..'

source: Learn English with Let's Talk    2017年4月28日
In this ESL lesson, Niharika will help you improve your spoken English. She explains what are the different alternatives to the old phrase “I don’t know” which doesn’t sound very bright, we can use several other English phrases which sound much more conversational and smart. We can use these English phrases while situations that we may not know the answers to.

The first three phrases are
I have no idea
I have no clue
I haven’t the foggiest idea

All three of these phrases can be used when you really have no information at all and are even unable to guess what the answer to a question could be.

For example,
Do you know if john has broken up with Mary?

Now since you haven’t spoken to either of them, you have no information and you really can’t make a guess about something like this, so you could respond by saying, I have no idea or I have no clue or I haven’t the foggiest idea, which also means the same thing.

The next set of phrases can be used when again you don’t know the answer to a question and it doesn’t concern you at all, hence you are also very annoyed but you can’t be rude to the person asking you. So you could respond by saying

How should I know?
Don’t ask me
Search me

For example,
Do you know if our boss is divorced?
How should I know?

This is a perfect example, to answer by using any of the above mentioned three phrases

The next one is,
Your guess is as good as mine.

This phrase can be used when you know that the person asking you a question also has no idea about what the answer could be. So you are both sailing in the same boat.

For example,
Do you know if Peter will come to the party?
Here, you could answer by saying, your guess is as good as mine.

The next phrase is,
It beats me.

This can be used when you want to say that you don’t understand something and hence you don’t know the answer

For example,
Do you know the answer to this puzzle?
It beats me.
The next phrase is,
Not as far as I know.

You can use this phrase when someone asks you a question to confirm if the information that they have is correct or not but you have no information about the situation. So you could say, not as far as I know.

For example, if a colleague of yours has heard a rumor that one of your managers is quitting and wants to confirm with you,
I heard about Josh’s resignation, did you know?

Well, not as far as I know.
The last phrase is
Who knows.

This phrase can be used for questions which almost no one would have answer to like,

Do you know when the end of the world is?
So you could say who knows in response to a question like this, which nobody may have answer to.

So these are the English phrases that you can use instead of the not so smart phrase, I don’t know and sound confident in English speaking while responding to questions that you don’t have answers to.