it S1 W1 [used as subject or object]
used to refer to a thing, animal, situation, idea etc that has already been mentioned or is already known about:
'Where's your office?' 'It's on the third floor.'
I love the spring - it's a wonderful time of the year.
There were people crying, buildings on fire. It was terrible!
Don't blame me. It wasn't my idea.
This little beast is a lemur and it lives in Madagascar.
used to refer to the situation that someone is in now, or what is happening now:
I can't stand it any longer. I'm resigning.
How's it going, Bob? I haven't seen you for ages.
And the worst of it is the car isn't even paid for yet.
Stop it, you two. You're just being silly.
used as the subject or object of a verb when the real subject or object is later in the sentence:
It worries me the way he keeps changing his mind.
What's it like being a sailor?
Apparently it's cheaper to fly than to go by train.
It's a pity you couldn't come.
It seems that we are not welcome here.
I found it hard to concentrate.
used as the subject of a sentence when you are talking about the weather, the time, a distance etc:
Is it still raining?
It was 4 o'clock and the mail still hadn't come.
It's my birthday today.
It's over 200 miles from London to Manchester.
It gets dark very early in the winter.
It's three years since I last saw her.
used with the verb 'be' to emphasize that you are talking about one particular thing, person, group etc and not any other:
It's Lawrence you should be talking to.
It was malaria that killed him.
It was in New Zealand that Elizabeth first met Mr Cronje.
used to refer to a baby when you do not know what sex the baby is:
What will you call it if it's a boy?
used to say who a person is:
'Who's that over there?' 'It's Robert Morley.'
used to say who is speaking, especially on the telephone:
Hello, it's Frank here.
It's all right, it's only me.
used to refer to sex:
Have you done it with him yet?
9 also if it hadn't been for somebody/something
used to say who or what prevents or prevented something from happening:
We would have arrived much earlier if it hadn't been for the snow.
a particular ability or quality that is needed in order to do something:
In a job like advertising, you've either got it or you haven't!
used to say that something you expected to happen is actually going to happen:
This is it, boys, the moment we've been waiting for.
used to say that something is completely finished or that a situation cannot be changed:
That's it then. There's nothing more we can do.
used to tell someone that they are doing something correctly:
Slowly...slowly. Yeah, that's it.
c) also that does it
used when you are angry about a situation and you do not want it to continue:
That's it. I'm leaving.
to think you are more important than you are:
Just because he got a higher mark he really thinks he's it.