The structure be going to + base verb is one of the most important ways to talk about the future in English. It sits between the Present Continuous tense and the auxiliary verb will — it uses a form of be (am/is/are), which connects it to the present moment, to talk about something that belongs to the future.
It has two main jobs: expressing plans decided before the moment of speaking, and making predictions based on present evidence. Both jobs share the same core idea — there is a strong connection between the present situation and the future outcome.
When you have already decided to do something before the moment of speaking — you have a plan, an intention, an arrangement that is already in your mind — you use be going to. The decision was made in the past; you are just reporting it now.
Think of it this way: the plan already exists in your head before you open your mouth. You are not deciding at this moment — you are announcing a decision already made.
When you can see, hear, or feel evidence right now that tells you something is about to happen, you use be going to. You are not guessing — you are making a logical conclusion from what is in front of you. The evidence is visible; the outcome is almost certain.
Think of it as reading the signs. You see the dark clouds → you conclude it is going to rain. You see someone losing their balance → you know they are going to fall. The present evidence leads directly to the future conclusion.
✗ She going to leave. · He are going to retire. · They is going to open a restaurant.
✓ She is going to leave. · He is going to retire. · They are going to open a restaurant.
The verb be must agree with the subject. I → am. He/she/it and singular nouns → is. You/we/they and plural nouns → are. Omitting be entirely or using the wrong form are very common errors. Always include the correct form of be — the structure is be + going to + base verb, not just going to + base verb.
✗ She is going to studies medicine. · They are going to opening a restaurant. · He is going to retiring.
✓ She is going to study medicine. · They are going to open a restaurant. · He is going to retire.
After going to, the main verb is always in the base form — the same form you find in the dictionary. Never add -ing, -s/-es, or any other ending. The going to itself carries all the future meaning; the main verb simply needs to be in its simplest, unchanged form.
✗ Look at those clouds — it will rain. · Watch out — he will fall!
✓ Look at those clouds — it is going to rain. · Watch out — he is going to fall!
When you have present evidence that clearly points to a future outcome — dark clouds, someone losing their balance, a shaking ladder — English uses be going to, not will. Will is used for predictions based on general opinion or knowledge, without visible present evidence. The key distinction: be going to = I can see it happening; will = I think/believe it will happen.
✗ "The phone is ringing." — "OK, I am going to answer it." (wrong — this is a decision made right now)
✓ "The phone is ringing." — "OK, I will answer it." (correct — will for spontaneous decisions)
✓ "I am going to call her back tonight." (correct — a plan decided earlier)
Be going to is for plans decided before the moment of speaking. When you make a decision at the moment of speaking — in response to something you just heard or just thought of — you use will, not be going to. This distinction is covered in detail in the Going To vs Will exercise.