There are two tenses in English: past and present.
There are four present tense forms:
|Present simple||I work|
|Present continuous||I am working|
|Present perfect||I have worked|
|Present perfect continuous||I have been working|
We can use all these forms:
- to talk about the present:
London is the capital of Britain.
He works at McDonald’s.
He is working at McDonald's.
He has worked there for three months now.
He has been working there for three months now.
- to talk about the future:
The next train leaves this evening at 17.00.
I'll phone you when I get home.
He is meeting Peter in town this afternoon.
I'll come home as soon as I have finished work.
You will be tired out after you have been working all night.
We can use present forms to talk about the past:
- when we are telling a story:
Well, it's a lovely day and I'm just walking down the street when I see this funny guy walking towards me. Obviously he's been drinking, because he's moving from side to side …
- when we are summarising something we have read, heard or seen:
I love Ian Rankin's novels. He writes about this detective called Rebus. Rebus lives in Edinburgh and he's a brilliant detective, but he's always getting into trouble. In one book, he gets suspended and they tell him to stop working on this case. But he takes no notice …