1. We use the present simple:
- to talk about something happening regularly in the present:
The children come home from school at about four.
We often see your brother at work.
- to talk about something happening continually in the present:
They live next door to us.
He works for the Post Office.
- to talk about things which are generally or always true:
Water boils at 100 degrees Celsius.
The Nile is the longest river in Africa.
2. We use the present continuous:
- to show that something in the present is temporary:
We are living in a rented flat at present.
My wife usually goes in to the office, but she is working at home today.
- for something happening regularly in the present before and after a given time:
I’m usually getting ready for work at eight o’clock.
When I see George he’s always reading his newspaper.
- for something happening before and after the moment of speaking:
I can’t hear you. I’m listening to my iPod.
Be quiet. The children are sleeping.
3. We use modal verbs
- to talk about the present when we are not sure of something:
I don’t know where Henry is. He might be playing tennis.
Who’s knocking at the door? I don’t know. It could be the police.