When we talk about future events which have already been planned or decided, or which we can see are on the way, we often use present tenses.
The present continuous
The present continuous is used mostly to talk about personal arrangements and fixed plans, especially when the time and place have been decided.
- What are you doing this weekend?
- I am seeing Alice tomorrow.
- What are we having for dinner?
The simple present
The simple present can be used to talk about future events which are part of a timetable.
- The train leaves at half past six tomorrow morning.
- What time does the bus arrive in Chennai?
- The summer term starts on April 10th.
Be going + infinitive
The structure be going to can be used to talk about plans, especially in an informal style. Going to puts an emphasis on the idea of intention.
- When are you going to get a job?
- We are going to buy a new home.
- John says he is going to call in this evening.
The going to structure can also be used to predict the future on the basis of present evidence.
- She is going to have a baby in June.
- Look at the sky. It is going to rain.
Present continuous and be going to: differences
The present continuous emphasises the idea of fixed arrangement; going to emphasises the idea of intention or previous decision.
- I am getting a new job. (It is already arranged.)
- I am going to get a new job. (I have decided to.)
- Who is cooking lunch? (asking about arrangements)
- Who is going to cook lunch? (asking about a decision)
We do not normally use the present continuous to make predictions about events that are outside people’s control.
- It is going to rain. (NOT It is raining.)
- Look out! We are going to crash. (NOT we are crashing.)
- Things are going to get better soon. (NOT Things are getting better soon.)
The present progressive and be going to can both be used to insist that people do things or do not do things.
- She is taking/going to take that medicine whether she likes it or not.
- You are not wearing/going to wear that skirt to school.
- You are not coming/going to come with me.
Simple future and present progressive: differences
Often shall/will and present-tense forms are possible with similar meanings.
- What will you do next year?
- What are you doing next year?
- What are you going to do next year?
We prefer present tenses when we are talking about future events that have already been arranged.
- I am seeing Alice on Wednesday. (The arrangement exits now.)
In predictions, we use going to when we have outside evidence for what we say. We prefer will when we are talking about what we know, or believe or have calculated.
- Look out. He is going to fall. (There is outside evidence.)
- Don’t lend him your car. He is a terrible driver. He will crash it. (the speaker’s opinion)