Will vs Going To Error Correction

First, identify the reason for the future form. If the sentence shows a decision made at the moment of speaking, an offer, or a promise, use "will" or "'ll." If it shows a plan decided before speaking, use "going to." If the sentence gives visible evidence now, use "going to" for the prediction. If it only gives an opinion such as "I think" or "probably," use "will." Do not change extra words unless they are part of the same future-form mistake.

In a gap-fill exercise, you already know where the future form belongs. In proofreading, you must first decide whether anything is wrong. That means you need to read the whole sentence for context clues: earlier decisions, present evidence, promises, offers, or opinion markers. This is why the exercise includes a few already-correct sentences. They train you not to change a correct future form just because another form is also familiar.

Yes, real speakers sometimes use both forms for predictions, especially when the context is not very specific. In this exercise, each sentence gives a clear clue so the correction is exam-focused: visible evidence points to "going to," while opinion or belief points to "will." The aim is not to memorise one form as always better, but to match the future form to the meaning in the sentence.