To Be Going To

To be going to is used to express a certainly future. 


Example: You have to go to the doctor and you called him. 


You're going to the doctor.
She is going to the doctor.
It is going to rain.
We're going to the beach.
They're going to the church.


When we use the Going To, we mean that the actions is planed. 


You never use Going To without the To Be Verb. 

Remember the To Be Verb

Subject	To Be Verb	Contract Form
I	Am	I’m
You	Are	You’re
He	Is	He’s
She	Is	She’s
It	Is	It’s
We	Are	We’re
You	Are	You’re
They	Are	They’re

Exemples of phrases with the TO BE verb:

I am a doctor. (Affirmative Form)

I am not a doctor. (Negative Form)

Am I a doctor? (Interrogative Form)

Note: Always when you see the TO BE verb in the phrase, it has to make part of any construction you do.

Another Exemple:

It is an apple. (Affirmative Form)

It is not an apple. (Negative Form)

Is it an apple? (Interrogative Form)