1.-To express habits, general truths, repeated actions or unchanging situations, emotions and wishes:
EX.-
I smoke (habit); I work in London (unchanging situation); London is a large city (general truth)
2.-To give instructions or directions:
EX.-
You walk for two hundred meters, then you turn left.
3.-To express fixed arrangements, present or future:
EX.-
Your exam starts at 09.00
4.-To express future time, after some conjunctions: after, when, before, as soon as, until:
EX.-
He'll give it to you when you come next Saturday.
