We use present simple for:
- facts which are true all the time: The sun rises in the east. The bus doesn’t go past my house.
- habits and routines: I study for about an hour a week. We never get much homework.
- opinions and beliefs: Do you agree? I don’t know the answer.
We use present continuous for:
- actions which are in progress at the moment of speaking: Why are you carrying an umbrella? It’s not raining.
- actions or situations around the moment of speaking: He‘s studying Russian at university.
- future arrangements: I’m meeting Andrew tonight.
States and actions
The present continuous is not normally used to describe:
- mental states: know, agree, understand, believe, etc.
- likes and preferences: like, want, love, hate, need, need, prefer, etc.
- other states: be, own, belong, forget, hear, seem, depend, etc.
Some verbs (e.g. think, see, have) can be used as states or actions, with different meanings:
- State: I think you’re wrong. (= my opinion )
- Action: I’m thinking about my birthday. (= a mental process)
- State: I see what you mean. (= I understand)
- Action: I’m seeing the doctor tomorrow. (= I’m meeting him/her)
- State: I have a car / a sister. (= possession, relationship, etc.)
- Action: I’m having a party / a shower / dinner.