I have the following sentence:

If T had still been alive, there is the great possibility that either T or C ...

My teacher says that the word "then" must appear after the comma, but I think that it's implied and unnecessary. Who is right?

  • 40
    I think your teacher was speaking of Visual Basic, not English :)
    – b.roth
    Commented Dec 13, 2010 at 16:17
  • 38
    If you're happy and you know it, clap your hands...
    – RegDwigнt
    Commented Dec 13, 2010 at 16:57
  • 3
    I was always told not to put in "then" when writing documentation as it made it look too much like the code. Commented Dec 13, 2010 at 17:38
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    You could start saying this instead: "If, parenthesis, T had still been alive, end parenthesis, curly brace, there is the great possibily that either T or C ..., end curly brace." Just to annoy your teacher [especially if he knows programming]. :) Commented Dec 18, 2010 at 1:53
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    It would be interesting if an answer could explain when "then" is to be preferred and when it is not; there is more to it than "it is not required". Commented Mar 11, 2011 at 18:11

3 Answers 3


It is not necessary to use then to introduce the consequence of the if clause:

If you build it, they will come.

If it ain't broke, don't fix it.

If I give you five dollars a week, you'll have over $250 by the end of the year.

All those are grammatically correct and clear (even the one with ain't, which I threw in for a grin.).

  • 2
    Robusto is correct. Frequently, at least in modern American usage, "then" is associated with someone is being serious or a little upset. e.g. "If you keep drinking, then I want you out of my house." or "If you ate the last banana, then you should have bought more!"
    – leoger
    Commented Dec 13, 2010 at 18:53
  • +1 Absolutely correct. The "then" is often implied in "if" clauses. Commented Dec 13, 2010 at 21:38
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    @J.M. If not, then don't. ;) Commented Dec 18, 2010 at 1:55
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    As said here @muntoo, the "then" can (usually) be removed with no loss of clarity: "If not, don't" ;D
    – user730
    Commented Dec 18, 2010 at 2:16

You can easily answer this backwards.


I will go, if you go.

I can simply flip it and say

If you go, I will go

I don't see myself obligated to write "then" in the second sentence!
If that is true, then I should have "then" in the first sentence, too! Your teacher is probably trying to come up with a reason why he took points off.

  • 3
    What a mean teacher. Commented Dec 18, 2010 at 1:56
  • 1
    Do those sentences need commas (- especially the first one)?
    – WAF
    Commented Feb 20, 2011 at 14:48
  • 1
    @WAF The first sentence does not require a comma.
    – WendiKidd
    Commented Jul 1, 2012 at 18:17

You. He/she is just being pedantic.

  • 6
    Isn't overly pedantic redundant? Wait, was that pedantic of me?
    – webbiedave
    Commented Dec 13, 2010 at 17:50
  • @webbiedave: possibly. :)
    – haylem
    Commented Dec 13, 2010 at 18:08
  • 4
    It does not seem to me that he/she is pedantic, but he/she is just wrong. Commented Dec 17, 2010 at 11:40
  • @TsuyoshiIto Thoug it seems that you can indeed use "then". See e.g. en.wikipedia.org/wiki/Conditional_sentence. It's just that the daily usage usually isn't like that.
    – xji
    Commented Jul 24, 2018 at 19:36

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