Future Simple - "will" vs "going to"

Look at those clouds! It --will rainis going to rain soon.

I --will startam going to start a new job next week.

We --will visitare going to visit our grandparents this weekend.

He --is going to helpwill help you as soon as he finishes what he's doing.

They --are going to celebratewill celebrate their anniversary in Hawaii next year.

I think she --is going to winwill win the competition.

The forecast says it --will snowis going to snow tomorrow.

I --am going to buywill buy a new car next month; I've already saved up enough money.

The company --is going to expandwill expand into new markets by the end of the year.

Based on the symptoms, the doctor said he --will prescribeis going to prescribe some medication.