WILL and GOING TO

Usa-se GOING TO:
- quando se tem certeza do que vai acontecer, uma decisão já tomada.
Situação 1
- What color are you going to paint your kitchen? (Que cor você vai pintar sua cozinha?)
- I´m going to paint it white. (Vou pintá-la de branco.)
Situação 2
- What are you going to do after class tonight? (O que você vai fazer após a aula hoje à noite?)
- I´m going to stop by at my uncle´s house to pick up some books. (Vou passar na casa do meu tio para pegar alguns livros.)
- para se fazer previsões sobre o que vai acontecer.
I think the concert is going to be good. (Acho que o show vai ser bom.)
I think it´s going to rain. (Acho que vai chover.)
Usa-se WILL:
- com expressões como “I THINK”, “MAYBE”, “I´M SURE”.
I think you´ll do well on the test. (Acho que você irá bem na prova.)
Maybe I´ll go to the movies tonight. (Talvez eu vá ao cinema hoje à noite.)
I´m sure everything will be all right. (Tenho certeza de que tudo ficará bem.)
- para se oferecer a fazer algo.
The phone´s ringing! (O telefone está tocando.)
Don´t worry, I´ll get it. (Não se preocupe, eu atendo.)
- quando se resolve fazer algo na hora da fala.
- Sir, will you have red wine or white wine? (O senhor aceita vinho tinto ou branco?)
- Mmm, I´ll have red wine. (Mmm, aceito o vinho tinto.)
Well, I hope this tip will help you. If you have any doubts or questions, post your comments here and I’ll answer them ASAP (as soon as possible)!
Take care and hope to hear from you soon!

Exercício--Escolha as opções(frases) que melhor substituem as que estão no futuro simples(will):

1.I will talk to her in private.
a.I going to talk to her in private.
b.I´m going talk to her in private.
c.I´m going to talk to her in private.
 
2.You will have better friends.
 a.You´re going to have better friends.
b.You going to have better friends.
c.You´re going have better friends.

3.He won´t let it happen.
a.He is going to let it happen.
b.He´s not going to let it happen.
c.He not going to let it happen.

4.Will she take a test?
a.Is she going to take a test?
b.She going to take a test?
c.Is she going take a test?

5.It will make your dream come true.
a.It going to make your dream come true.
b.It´s going to make your dream come true.
c.It´s not going to make your dream come true.

6.They will tell you what to do.
a.They´re going to tell you what to do.
b.They is going to tell you what to do.
c.They´re going tell you what to do.

7.Flamengo will win.
a.Flamengo is goin to win.
b.Flamengo going to win.
c.Flamengo is going to win.

retirei daqui