"If you happen to... [+ imperative/could you...]"

Hi, MlleSim,

@MlleSim posted:

"If you happen to [do X], could you please [do Y]?"

Yes, that is grammatical. On page 47 of Michael Vince's Advanced English Practice (Grammar Chapter 8 - Conditionals), we can read the following:

Excellent As usual, your swift and clear reply is most appreciated, Gustavo.

@MlleSim posted:

It is ungrammatical, though, to use a question beginning with "could you..." after a conditional clause?

If you don't mind my asking, MllSim, why did you think it might be ungrammatical to use a "Could you . . ." question after an "if"-clause?

I think the important thing here is to see that the "could"-question is being used to make a request of the hearer. That is the speech act it performs.

The request is a conditional one, contingent upon something's happening, or happening to happen. "Happen to" is just a raising verb, and is unnecessary.

• If you see apples, could you pick some up?
• If you happen to see apples, could you pick some up?
• If you happen to see apples, would you pick some up for me, please?
• If you see apples, it would be great if you could pick some up for me.

Of course, the request only works in the second person. The following does not work: "If he sees some apples, could he pick some up for me?"

@David, Moderator posted:

If you don't mind my asking, MllSim, why did you think it might be ungrammatical to use a "Could you . . ." question after an "if"-clause?

I do not mind at all. Do you remember our conversation a while ago about mixed tense sequences in conditional sentences (here)? I just became a bit puzzled when thinking about the use of a "could"-question after an "if"-clause using the present tense (since we did not discuss this sub-type in the thread). I use it all the time, but, still, we both know that I tend to question everything a tad too much.

I just realised, though, that I completely missed the section covering the use of modals in Type 1 constructions in L. G. Alexander's Longman English Grammar:

I certainly would not have posted my question had I found this when my doubt arose!

@David, Moderator posted:

Of course, the request only works in the second person. The following does not work: "If he sees some apples, could he pick some up for me?"

This is an interesting observation because, funnily enough, its ungrammaticality is not readily apparent to me... why could we not say this if, for example, it were the boy's sister speaking to their mother and she were asking her permission (because the mother pays)?

@MlleSim posted:

I do not mind at all. Do you remember our conversation a while ago about mixed tense sequences in conditional sentences (here)? I just became a bit puzzled when thinking about the use of a "could"-question after an "if"-clause using the present tense (since we did not discuss this sub-type in the thread). I use it all the time, but, still, we both know that I tend to question everything a tad too much. I

Thanks for explaining. I thought you might be worried a "mixed" conditional. I personally do not think such conditionals as these—conditional requests—are even candidates for being blacklisted by prescriptivists as "mixed" conditionals, because the part of the sentence with "could" is nonpropositional in nature; the question with "could" simply realizes the speech act of a request.

@MlleSim posted:

This is an interesting observation because, funnily enough, its ungrammaticality is not readily apparent to me... why could we not say this if, for example, it were the boy's sister speaking to their mother and she were asking her permission (because the mother pays)?

Yes, it isn't ungrammatical. By crossing it out in red, I didn't mean to indicate that it was ungrammatical, only that it didn't work at all as a request made of the referent of "he." You are right that special contexts can be imagined in which one is requesting someone with power over him to permit him to pick some apples up in the event that he sees apples. That type of context had occurred to me, even as I was in the process of dismissing the sentence.