Present tenses review

Present simple and present continuous:

We use the present simple to talk about:
* Facts and states.
   - The library doesn't close until 10 p.m.
   - I'm pretty tired right now.
* Habits and repeated actions.
   - I usually get up early.
   - I often meet friends.

We use the present continuous to talk about:
* Actions happening now.
   - I'm studying design and technology.
   - She's going to the library.
* Temporary situations.
   - At the moment, I'm living in a university building.
   - Right now, he's feeling a bit nervous.

Present perfect simple:

We use the present perfect simple:
* To talk about states, actions or events that started in the past and that continue in the present.
   - How long have you been here?
* To talk about something which happened in the past and which has an effect in the present.
   - She's passed her exams so she's going to university.
* To talk about past experiences, without saying exactly when they took place.
   - I've made a lot of new friends.