Hello! What is the difference between "to have to do smth" and "have got to do smth"?
And what is "got to to smth" and "gotta do smth"? Is it grammatically right or not? Because I heard this forms only in songs. =)
In my opinion:

Have to do sth and Have got to do sth somehow have the same meaning.
We use them to express our necessity in the present or the near future.
Have got to do sth is used especially in British English.
Ex: I have to leave now. (=I have got to leave now.)
Do you have to go there? (=Have you got to go there?)
We can use them to give advice or recommend something.
Ex: You have to try this book! It’s wonderful.(= You’ve got to try this book! It’s wonderful.)
Get to do sth = Be allowed to do sth
Ex: Before you get to watch TV, you have to do your homework. (=Before you are allowed to watch TV, you have to do your homework.)
Got to do sth is the Past form.
Ex: Before she got to go out, she had done all the housework. (=Before she was allowed to go out, she had had to do all the housework.)
About gotta do sth:
Each of the following sentences is faster to say than its previous one:
I have got to go.
I've got to go.
I've gotta go.
I gotta go.
Do not use gotta do sth in your writings. It's very ridiculous.
Thank you very muchEmotion: smile