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 at this evening at 1700 hours.
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.