11
  1. You won't catch the train if you don't leave in time
  2. You won't catch the train if you won't leave in time

I'm pretty sure the correct version is "You won't catch the train if you don't leave in time", but I'm trying to explain it to someone and I don't know how to explain it. I also don't know how to google it.

Can you please help me with a simple explanation or a link that explains it?

closed as off-topic by David, Davo, RaceYouAnytime, NVZ, Centaurus Aug 8 '17 at 0:22

This question appears to be off-topic. The users who voted to close gave this specific reason:

If this question can be reworded to fit the rules in the help center, please edit the question.

  • 3
    ...if you won't leave on time refers to someone's will and can be paraphrased as ...if you refuse to leave on time. I ...if you don't leave on time, don't leave is just the negative of leave. – AmE speaker Aug 6 '17 at 23:10
24

As implied in the comments, the specific meaning of the two are slightly different (albeit both grammatically correct). It helps to break down the contractions.

You will not catch the train if you do not leave on time

This phrase is neutral in its blame: not catching the train will happen if you, for whatever reason, do not leave on time.

You will not catch the train if you will not leave on time

This places blame more directly on addressee: 'will not' implies that the addressee plays a causal role in themselves being late for the train, as if they refuse to leave at the correct time.

4

You won't (will not) catch the train if: a. you don't (do not) leave in time. This allows for several circumstances to be the cause of the delay, and the warning serves generically to bring attention to the need for timeliness. b. you won't (will not) leave in time. This specifies that the person has control over their situation, and if they choose not to, then they will suffer the explained consequence.

Not the answer you're looking for? Browse other questions tagged or ask your own question.