We use the Present Simple for things that are true at any time. We use it for a general truth, or a fact:

• The melting point of ice is 0°C.
• Alan doesn’t sing very well, but he plays the violin beautifully.

We use the Present Continuous to say that an action is in progress now, at the moment of speaking:

• Look! That man is running from the policeman.
• Listen! Sylwia’s playing the accordion; she’s playing a sea shanty.

We use the Present Simple when we talk about a permanent situation, or an activity that is repeated again and again. We think it will continue for an unlimited time:

• What does Paul do? ~ Paul’s a writer; he writes horror novels.
• I work for a company that produces paper. We sell it all over the world.
• Amanda usually studies in the evenings.
• I stay with friends when I travel to America on business.

We use the Present Continuous to describe a current activity or situation that is unusual or temporary. We know it will continue for a limited period of time from now:

• Paul is writing his latest novel. He hopes to finish it next week.
• I don’t usually work at the weekends, but I’m working on Saturdays this month.
• Amanda’s studying all day. She has an important exam to prepare for.
• I’m staying with my friends until I can find a flat of my own.

We use the Present Simple with words like always, usually, often, etc. when we talk about how often we do something:

• Amanda sometimes studies all day, but she usually studies in the evenings.

We can use the Present Continuous with always to say that something happens too often:

• Peter is always watching TV.
• Our neighbours are always playing loud music.