PRESENT PERFECT SIMPLE

USE

puts emphasis on the result
Example: She has written five letters.

action that is still going on
Example: School has not started yet.

action that stopped recently
Example: She has cooked dinner.
f

inished action that has an influence on the present
Example: I have lost my key.

action that has taken place once, never or several times before the moment of speaking
Example: I have never been to Australia.

PRESENT PERFECT CONTINUOUS

We use the Present Perfect Continuous to show that something started in the past and has continued up until now. "For five minutes," "for two weeks," and "since Tuesday" are all durations which can be used with the Present Perfect Continuous.

Examples:

They have been talking for the last hour.
She has been working at that company for three years.
What have you been doing for the last 30 minutes?
James has been teaching at the university since June.
We have been waiting here for over two hours!
Why has Nancy not been taking her medicine for the last three days?

cresdits:English Grammar Book

WILL
Simple Future has two different forms in English: "will" and "be going to." Although the two forms can sometimes be used interchangeably, they often express two very different meanings. These different meanings might seem too abstract at first, but with time and practice, the differences will become clear. Both "will" and "be going to" refer to a specific time in the future.

Examples:

You will help him later.
Will you help him later?
You will not help him later. lear. Both "will" and "be going to" refer to a specific time in the future.
GOING TO
Use
1) planned actions in the future
We are going to sing at the party.

2) You are certain that sth. is going to happen in the future.
Look at this car! It is going to crash into the yellow one.

Examples

Affirmative sentences:
I am going to play handball.I'm going to play handball.
You are going to play handball.You're going to play handball.

Negative sentences:
I am not going to play handball.I'm not going to play handball.
You are not going to play handball.You're not going to play handball.You aren't going to play handball.

Questions:
Am I going to play handball?
Are you going to play handball?
credits:English Grammar Book

PRESENT SIMPLE
Use the Simple Present to express the idea that an action is repeated or usual. The action can be a habit, a hobby, a daily event, a scheduled event or something that often happens. It can also be something a person often forgets or usually does not do.

Examples:

I play tennis.
She does not play tennis.
Does he play tennis?
The train leaves every morning at 8 AM.
The train does not leave at 9 AM.
When does the train usually leave?
She always forgets her purse.
He never forgets his wallet.
Every twelve months, the Earth circles the Sun.
Does the Sun circle the Earth?
PRESENT CONTINUOUS
Use the Present Continuous with Normal Verbs to express the idea that something is happening now, at this very moment. It can also be used to show that something is not happening now.
Examples:
You are learning English now.
You are not swimming now.
Are you sleeping?
I am sitting.
I am not standing.
Is he sitting or standing?
They are reading their books.
They are not watching television.
What are you doing?
Why aren't you doing your homework?
credits:English Grammar Book