1) Present Simple is used to talk about:
- Habits (my father drives to work)
- How often things happen (It never snows in the Sahara desert)
- Permanent situations (I live in London)
- General truths and facts (Water boils at 100 C)
- General abilities (I play the piano)
- States - thinking, emotions, the human senses, appearance, relationships between things (I know him and his brother; I see much better with my new glasses)
- The future in timetables (My train leaves in an hour)
- The future in time clauses (I'll tell Carrie when I see her)
2) Present Continuous is used to talk about:
- Actions in progress at the moment of speaking (come inside - it's raining)
- Temporary series of actions (I am learning to drive)
- Temporary situations (We are staying at the Grand Hotel)
- Changing situations (This city is getting bigger every year)
- Annoying habits (usually with always) (You are always losing your keys!)
- Definite arrangements and plans for the future (We are having a test tomorrow)
3) Modal verbs are auxiliary verbs which express things like possibility, obligation, etc.
Modal verbs:
- Don't change for person or tense (He might go to the cinema(not he mights)
- Don't use do in questions (Can you play the guitar?(not do you can play)
- Are followed by the bare infinitive (without to) (I think he will call.. (not he will to call)
- Don't have an infinitive (I hope to be able to attend the meeting (not I hope to can attend...)
Modal verbs include will, would, can, could, may,should, must, might, shall and ought to.
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