She used to be a varsity athlete.

In a grammar book, the above sentence was listed among sentences containing at least one auxiliary verb. If "used" is indeed the auxiliary verb, can an infinitive be used as a main verb? Something seems off here.

  • @EdwinAshworth The verb is "use", not "used to". (The bracketing with, for example, past tense "used" is "[I used [to smoke"]]. It's an auxiliary verb for some speakers, but a lexical verb for most. It all depends on whether you can say "Used you to live near there?" and "It usedn't to be allowed"..
    – BillJ
    Commented Dec 22, 2023 at 8:44
  • 1
    @BillJ Well, I agree, but there's also usedta, clearly alluded to but not actually listed in footnote 34 of page 1227 of CGEL, which is one of the verbs studied in Pullum's "The morpholexical nature of to-contraction". There's some lighthearted discussion on Language Log, here. It's definitely one word for some users sometimes. Commented Dec 22, 2023 at 11:48
  • @BillJ It doesn't 'all depend'. There are different tests one can use; emphasis is on used to not used in stressed speech, arguing for cohesiveness. I can't wait for the next great work on grammar that eclipses CGEL, and wonder if its adherents will be as dismissive of other approaches as some now are. Commented Dec 22, 2023 at 11:53
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    @BillJ 'It can only be ...'. The splitting / lumping debate will doubtless continue for many years (if we have that long left). CGEL is happy to split FANBOYS (and few serious linguists would argue there); ing-forms on the N ... V cline and verbs functioning in 'auxiliary positions' are areas some deem worthy of better refinement. // Grammar differences set aside, have a good Christmas (I'll not offer to play football). Commented Dec 22, 2023 at 15:14
  • 1
    @EdwinAshworth Thanks. And you.
    – BillJ
    Commented Dec 22, 2023 at 15:44

1 Answer 1


There's up to three auxiliary verbs in your sentence, depending on what grammar you subscribe to, or who you pay your dues to, as Professor Lawler used to say.

The verb used is sometimes an auxiliary verb for some speakers. It's not possible to say whether it is in your sentence because there is no subject-auxiliary inversion and no negation and no ellpsis.

The word to is considered a non-finite auxiliary verb by many grammarians, for example in HPSG, Sign-Based Construction Grammar and by authors like Geoffrey K Pullum.

Lastly, the verb be is considered an auxiliary by most modern grammarians even when used without a following verb (i.e. when used in a copula construction as in your example, where be is taking a noun phrase as a predicative complement). So - take your pick!

Regarding your second question, "main verb" is a bit passé nowadays. However, seeing as verbs like ought are considered auxiliaries and take to-infinitives, it shouldn't be a problem with used. The main criteria for auxiliariness make no reference to the form of the complement of the verb, and thus we don't need to consider it here.

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    "X used to be" cannot be an auxiliary. What would it be "helping"? And what is the sentence's verb?
    – Lambie
    Commented Dec 21, 2023 at 16:03
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    @Lambie Etymological fallacy. [Also "X used to be" cannot be an auxiliary because it is four words!] And there's no use busting me about this, I'm just letting you know what the grammarians say about these items! Commented Dec 21, 2023 at 16:08
  • But my idea is not etymology. It's semantic. Yes, x used to [verb], sure.
    – Lambie
    Commented Dec 21, 2023 at 16:37
  • 2
    @Lambie Some speakers accept sentences like "Used he to live there?". In sentences like that, the verb use undergoes subject-auxiliary inversion and is thus an auxiliary. Huddleston & Pullum mention this usage; I think I've heard it before but it strikes me as extremely uncommon.
    – alphabet
    Commented Dec 21, 2023 at 23:34
  • @alphabet That is really specious. H&P often go overboard.
    – Lambie
    Commented Dec 21, 2023 at 23:50

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