Present Tense - English Grammar

THE SIMPLE PRESENT TENSE IS USED:
To express habits, general truths, repeated actions or unchanging situations, emotions and wishes:
I smoke (habit);
I work in London (unchanging situation);
London is a large city (general truth) To give instructions or directions:
You walk for two hundred meters, then you turn left.

To express fixed arrangements, present or future:
Your exam starts at 09.00

To express future time, after some conjunctions: after, when, before, as soon as, until:
He'll give it to you when you come next Saturday.

Be careful! The simple present is not used to express actions happening now.
EXAMPLES For habits:
He drinks tea at breakfast.
She only eats fish.
They watch television regularly.

For repeated actions or events:
We catch the bus every morning.
It rains every afternoon in the hot season.
They drive to Monaco every summer.

For general truths Water freezes at zero degrees:
The Earth revolves around the Sun.
Her mother is Peruvian.

For instructions or directions:
Open the packet and pour the contents into hot water.
You take the No.6 bus to Watney and then the No.10 to Bedford.

For fixed arrangements:
His mother arrives tomorrow.
Our holiday starts on the 26th March.

With future constructions:
She'll see you before she leaves.
We'll give it to her when she arrives.