GRAMMAR

source video :https://www.youtube.com/watch?v=nvVdIJ0las0

1.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. source:https://www.ef.com/wwen/english-resources/english-grammar/simple-present-tense/

source:https://www.youtube.com/watch?v=AKzG_ZS-Ydg

2.The present continuous is used:

to describe an action that is going on at this moment: You are using the Internet. You are studying English grammar.
to describe an action that is going on during this period of time or a trend: Are you still working for the same company? More and more people are becoming vegetarian.
to describe an action or event in the future, which has already been planned or prepared: We're going on holiday tomorrow. I'm meeting my boyfriend tonight. Are they visiting you next winter?
to describe a temporary event or situation: He usually plays the drums, but he's playing bass guitar tonight. The weather forecast was good, but it's raining at the moment.
with "always, forever, constantly", to describe and emphasise a continuing series of repeated actions: Harry and Sally are always arguing! You're constantly complaining about your mother-in-law!. source:https://www.ef.com/wwen/english-resources/english-grammar/present-continuous/

source:https://www.youtube.com/watch?v=MI3S3kdkofo

3.the simple past tense

The simple past tense, sometimes called the preterite, is used to talk about a completed action in a time before now. The simple past is the basic form of past tense in English. The time of the action can be in the recent past or the distant past and action duration is not important.

You always use the simple past when you say when something happened, so it is associated with certain past time expressions
frequency: often, sometimes, always
I sometimes walked home at lunchtime.
I often brought my lunch to school.
a definite point in time: last week, when I was a child, yesterday, six weeks ago
We saw a good film last week.
Yesterday, I arrived in Geneva.
She finished her work atseven o'clock
I went to the theatre last night
an indefinite point in time: the other day, ages ago, a long time ago
People lived in caves a long time ago.
She played the piano when she was a child.
Note: the word ago is a useful way of expressing the distance into the past. It is placed after the period of time: a week ago, three years ago, a minute ago. source:https://www.ef.com/wwen/english-resources/english-grammar/simple-past-tense/

source:https://www.youtube.com/watch?v=n14zCZAvSjI

source:https://www.youtube.com/watch?v=IpmmTWcjVbM

4.the simple future tense

The simple future refers to a time later than now, and expresses facts or certainty. In this case there is no 'attitude'.

The simple future is used:

To predict a future event:
It will rain tomorrow.
With I or We, to express a spontaneous decision:
I'll pay for the tickets by credit card.
To express willingness:
I'll do the washing-up.
He'll carry your bag for you.
In the negative form, to express unwillingness:
The baby won't eat his soup.
I won't leave until I've seen the manager!
With I in the interrogative form using "shall", to make an offer:
Shall I open the window?
With we in the interrogative form using "shall", to make a suggestion:
Shall we go to the cinema tonight?
With I in the interrogative form using "shall", to ask for advice or instructions:
What shall I tell the boss about this money?
With you, to give orders:
You will do exactly as I say.
With you in the interrogative form, to give an invitation:
Will you come to the dance with me?
Will you marry me?

Note:In modern English will is preferred to shall. Shall is mainly used with I and we to make an offer or suggestion, or to ask for advice (see examples above). With the other persons (you, he, she, they) shall is only used in literary or poetic situations, e.g. "With rings on her fingers and bells on her toes, She shall have music wherever she goes."

source:https://www.ef.com/wwen/english-resources/english-grammar/simple-future-tense/