a) I am going to cut my birthday cake

b) Jane is going to light the candles

c) My sister is going to turn off the lights

d) My friends are going to sing "happy birthday to you"

e) I am going to blow out the candles

f) Each person is going to eat a piece of cake

g) They are going to drink coke or juice

h) But the dog is going to do something terrible

i) It is going to be a tragedy

j) We are going to run after the god (Sinceramente eu não entendi essa frase)

Basta prestar atenção no sujeito da frase pra selecionar o verbo to be adequado, adicionar o going to e o verbo no infinitivo, exatamente como está entre os parênteses

Abraço!