I am struggling to decide the correct tense / verb usage where one wishes to express some past plan for the then future:

  1. We agreed that, when xyz happens, we would do abc.

  2. We agreed that, when xyz happened, we would do abc.

  3. Something else?

According to Future in the Past, the second form is correct because one must use Simple Past with clauses that begin with time expressions (such as "when"). This assessment is somewhat supported by this answer, which suggests that the past tense must be used since xyz has already occurred and is now in the past.

However, to my mind, the second form doesn't quite convey the same contingency that abc would not be done until xyz happened; whereas the use of the present tense in the first form better conveys that contingency.

Are grammatical constructs of this sort known by some formal name? What do authorities on English (especially British English) have to say on the matter (citations would be most welcome)?

  • The British do not have a view of time that is distinct to them amongst Anglophones.
    – tchrist
    Commented Jul 20, 2013 at 12:17
  • Is the "then future" also the "current future"? This makes a difference. Commented Jul 20, 2013 at 13:10
  • @PeterShor: No, the "then future" is now the "current past". :)
    – eggyal
    Commented Jul 20, 2013 at 22:14

3 Answers 3


We agreed that, when xyz happens, we would do abc

This sentence does not make sense to me. If ‘happens’ is present tense, xyz clearly is still in the future (or is a general statement, ‘when’ meaning in effect ‘whenever’). Therefore, ‘do’ should also be in the future (or present) tense, rather than in the conditional mood:

We agreed that, when xyz happens, we will do abc
We agreed that, when xyz happens, we do abc

Having ‘happens’ in the present, but ‘do’ in the conditional creates an impossible time line, and the sentence collapses semantically. (Although in colloquial language use, I’m sure you’d be quite likely to hear it used)

However, since you say that xyz was future when the agreement was made, but is now past, this is not the proper option to begin with.

We agreed that, when xyz happened, we would do abc

I’m not sure what contingency it is you feel is not expressed here. If you know for a fact that xyz has in fact happened at the time of reporting, there is no contingency to express: it is an at the time future event that is now marked as having actually happened.

In general, I feel the sentence would flow better if the latter two phrases were reversed:

We agreed that we would do abc when xyz happened

But that is a matter of style alone.

As for your last question, I am not aware of any particular grammatical term for the interaction between such constructions, but I’m sure someone has coined one somewhere.

  • 1
    Whether reversing the last two phrases is better style really depends on the surrounding sentences. It's not something you should judge out of context. Commented Jul 20, 2013 at 13:18
  • Janus, how about "We agreed that we would have done abc when xyz happened"? Is not it better in the light of the supposed context in which that sentence occurred in the OP's ears?
    – user19148
    Commented Jul 20, 2013 at 13:36
  • 1
    @Carlo_R.: No, that means something else. If they agreed that they would have done something else when xyz happened, that is a different order of things: 1) making the agreement; 2) doing xyz; 3) _abc happening. That is not the order presented by the OP. Besides, ‘would have done’ implies only an actual fact of one thing being before the other. An agreement of something in the future cannot do this, so you would instead say ‘should have done’. Commented Jul 20, 2013 at 13:42
  • I don't see why when xyz happens would cause a semantic collapse. It just implies that xyz will definitely happen at some point. For example: We agreed that when grandma dies, we will scatter her ashes over the sea.
    – terdon
    Commented Jul 20, 2013 at 14:32
  • @terdon, the collapse is because xyz is in the future, but abc, the thing you will do after xyz has happened, is in the past. In your example, both ‘dies’ and ‘will scatter’ is in the future, and there is no collapse. If you say, “We agreed that when grandma dies, we would scatter her ashes over the sea”, the tenses don’t match up any more (although, again, I’m sure lots of people would say it without thinking that far). Commented Jul 20, 2013 at 14:48

How about:

We had agreed that, when xyz happened, we would do abc.

Analysis of grammar is not my forte, so no guarantees as to whether this suggestion is either correct or appropriate; but, my understanding is that there you have three tenses:

past perfect - past simple - conditional

which I think conveys the correct sequence of events.

  • 1
    If you use the past perfect, you are saying that “at the time that I am talking about now, we had already agreed that …”, which is not the same as saying simply that “we agreed that …”. Commented Jul 20, 2013 at 13:44
  • In which case, since we do not know the surrounding context, either form could be correct?
    – TrevorD
    Commented Jul 20, 2013 at 13:52
  • 1
    It could be, of course; but it is different from what the asker has in the question, so we cannot assume it to be. Commented Jul 20, 2013 at 13:58
  • Agreed, but experience on this site shows that, especially for non-native OPs (& I don't know whether this OP is native or not), it can sometimes be rash to assume that OP means exactly what we interpret the words to mean - sometimes simply because they haven't thought it through or don't understand what other options there could be. This is why more context is always useful - or indeed critical at times. So I wouldn't automatically rule out other options just because OP hasn't clearly expressed them.
    – TrevorD
    Commented Jul 20, 2013 at 15:16
  • In this case, I am native and did indeed mean to express the making of an agreement at the moment in question.
    – eggyal
    Commented Jul 21, 2013 at 7:37

Why not

We had agreed that, when xyz will have happened, we will do abc.

This coveys that the agreement is most distant in the past, anticipates an event in the future from the agreement that needs to be completed (but one which will occur, not maybe occur), which will then inevitably (not perhaps) lead to an event future from the condition, but not necessarily future from today.

  • Sorry, that really doesn’t scan for me.
    – tchrist
    Commented Jul 20, 2013 at 16:27
  • Nor for me. While it does make sense semantically (or at least … I think it does), the composition of tenses makes the whole sentence far too complex to even be comprehensible without thorough analysis. -1 Commented Jul 20, 2013 at 16:33

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