I'm trying to explain how to contrast the following two sentences in a meaningful - detailed - way.

I was eating when a bee stung me.

I was eating when I was on a break.

The intention is to teach ESL learners to understand that the first as an "interruption" statement but the second is not.
I'd like to avoid saying "you just have to understand the context".
I feel like the function is different enough that maybe, maybe we can.

Is there a way to define a difference in those two
"when" clauses
to predict the function
based on the grammar of the clause or words?

  • Did this stuff come up in a lesson in a textbook? Nov 16, 2015 at 13:33
  • 2
    The second is durative stative, so while can be used, while the first is punctual active, so while won't work. The punctual "interruption" sense of when can be replaced by and, because simple time order provides the same effect. Nov 16, 2015 at 17:03
  • I would spend some attention on the word on in "on a break". On the phone, on holiday, on a break, on and on.
    – TimR
    Nov 16, 2015 at 17:56
  • @michael_timofeev -- nope :) just in class
    – Mike M
    Nov 17, 2015 at 1:05
  • @JohnLawler- I appreciate those details. Rewriting with "while" certainly makes sense to prevent the question.... I'm really curious if there's any way to answer it as it is... ( I won't be surprised if there is or there isn't )
    – Mike M
    Nov 17, 2015 at 1:07

1 Answer 1


[1] I was eating, when a bee stung me.

[2] I was eating when I was on a break.

The when phrases are both adjuncts, but the difference is that in [1] the phrase is a supplement, and in [2] it’s a modifier.

In [2] we have a phrase that is tightly integrated into the structure of the clause, an indispensable part of it. It’s restrictive in that it denotes precisely when I was eating: I was not eating at some random time, but specifically when I was on a break.

By contrast, in [1] we have a non-integrated loosely attached phrase giving some useful but non-essential information. It doesn’t define when you were eating; rather it says that you were eating, and while you were, you happened to be stung by a bee. Loose adjuncts of this kind are called supplements. I’d recommend inserting a comma as shown to mark it as a supplement as opposed to a modifier. In speech, it would typically be marked off by what is perceived as a slight pause. By virtue of being non-integrated, it is semantically non-restrictive.

  • Thanks for all these details. I'm definitely trying to learn this terminology here. What you've done though is unexpectedly add the corollary of whether or not we can add a comma in #1 :-) My informal opinion thinks that using the comma is the answer to separating the two cases. But I didn't put it in my question because several people I've talked to in person say it isn't allowed. Can you point me to some other references that talk about using that comma?
    – Mike M
    Nov 17, 2015 at 1:10
  • @MikeM the problem you are still going to run into is the valid student question about the use of the word "when." It's all fine and dandy to discuss the clauses and commas but the students are going to come from a practical standpoint and ask for a rule of some sort, or you will find that they start using "when" in ways not acceptable. I haven't had to teach this in a while but when I last did there were all sorts of valid questions about when while and during. Nov 17, 2015 at 1:28
  • @michael_timofeev -- absolutely. But first things first --- can we find a rule for reading these sentences that doesn't quite depend on "just knowing". Clearly since any answer - if there is one - will be pretty exotic, it will only be useful for the 2 students that are advanced enough to have asked it. But I promised to find one, so here we are :-)
    – Mike M
    Nov 17, 2015 at 8:35
  • @MikeM yes, I would love to have a generally applicable observation. Professor Lawler's answer gave me some food for thought. I'm hoping some others will comment on this question. Personally, I hate telling students something is idiomatic or you just have to be exposed enough...I prefer to give guidelines and ideas to help them see that English isn't so random and that they can speak it. Nov 17, 2015 at 8:48
  • @MikeM I don't think there's any doubt that in speech the supplement would be set off by a slight pause, so there's no reason why you can't mark it in writing as a supp by popping in a comma. Most supps are set off that way. Although both when clauses are adjuncts, optional elements rather than obligatory, a pause/comma are still the best indicators here.
    – BillJ
    Nov 17, 2015 at 9:23

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