Can you explain to me whether I should or should not use ‑s at the end of the verb allow in this sentence?

This function requires that the container class allow[s] random access

The sentence in the book I read wrote allow without ‑s. However, the container class is a third-person singular, so the ‑s must be required. Is that right?

  • 2
    That verb requires that the verb in its subordinate clause be of the untensed or subjunctive flavor. You don’t inflect it. This is asked every single day here. It’s time we demand the heads of the authors of the ESL texts that neglect the mandative subjunctive.
    – tchrist
    Aug 9 '15 at 17:51
  • 1
    Subjunctive is possible, but this is mainly an Americanism, which, of course, is not bad in itself. British has moved on however and allows the third-person singular inflection, popularly known as the shit rule (short for she-he-it), so it's mainly a matter of preference whether you would opt for the slightly more archaic subjunctive, which, despite my revered colleague @tchrist's pertinence, is not required, or the rather more modern British feel of "allows". Aug 9 '15 at 18:01
  • 1
    @JoostKiefte That’s ungrammatical here (read: it sounds to the American ear like an illiterate bumpkin wrote it, not a native speaker), and indeed careful British writers still use it. This question is a duplicate of english.stackexchange.com/q/76550 and should be closed as such.
    – tchrist
    Aug 9 '15 at 18:02
  • 3
    @JoostKiefte tchrist is correct: here the indicative would sound uneducated to the North American ear - not archaic at all. It's true that the mandative subjunctive is obsolescing, being superseded by infinitival constructions (I've asked him to be there replacing I've asked that he be there), but it is by no means obsolete and is not being replaced by the indicative.
    – Anonym
    Aug 9 '15 at 18:33
  • 1
    @Joost Kiefte: by far the most common British construction is requires the container class to allow rather than requires that the container class allows (which I suspect is even rarer than the subjunctive in the U.K.) And it is absolutely fine in the U.S. as well. Aug 9 '15 at 22:03

This is an example of the subjunctive:

The Subjunctive is used to emphasize urgency or importance. It is used after certain expressions (see below).


I suggest that he study.
Is it essential that we be there?
Don recommended that you join the committee.


  • The subjunctive is used mainly by Americans. British has the rather less archaic and confusing "should + infinitive" construction: I suggest that he should study; is it essential that we should be there?; Don recommended that you should join the committe. The addition of "should" makes the urgency or desirability of the action at lot clearer. Aug 9 '15 at 18:21
  • Thanks for the additional usage notes! I was originally going to provide this page, which discusses changes in usage patterns: englishgrammar.org/subjunctive Since the original question was about whether the usage of this form was incorrect in a technical manual, this more detailed description of how subjunctive is used seemed more appropriate. As a native US English speaker, the concept of subjunctive never registered for me until studying it in French.
    – ecc
    Aug 9 '15 at 18:28
  • 1
    The "present subjunctive" is governed by impositive predicates; that's the "certain expressions" mentioned in the rule you cite. Aug 9 '15 at 19:26
  • @JoostKiefte Note that the mandative should + bare infinitive construction is at odds with the North American perception of the word should, which is interchangeable with to be supposed to and similar constructions. To my Canadian ear, the rules require that everyone should be there reads as the rules require that everyone be supposed to be there, which is just silly. Obviously perceptions differ from place to place, and obviously I adjust my expectations when reading foreign works, but your preferred construction is no less confusing to us than ours may be to you.
    – Anonym
    Aug 9 '15 at 20:57
  • @Anonym There is nothing against the substitution of should with must, which makes all perceived silliness disappear as fog burned off by the sun. Your subjunctive is not confusing to me, I just wouldn't use it myself other than with irony. I trust this exchange of our respective points of view will make the should + infinitive immediately clear to you in future, so be happy that you have learnt (or learned, if you so wish) something. I am. Aug 9 '15 at 21:23

No, it's fine without s. Requires that takes the subjunctive.

  • I would like to add that the subjunctive is peculiar to North American varieties of English. British would prefer "should" + (bare) infinitive. Aug 9 '15 at 21:28
  • @Joost Kiefte It's not peculiar to North American varieties of English in the exclusive sense. There are broad trends. And in everyday conversation in the UK, the 'mandatory subjunctive' is often replaced by the indicative (eg 'I insist that John goes with you'), where context disambiguates. Aug 10 '15 at 0:14

That is the case of Present Subjunctive in the sentences denoting requirement, advice, demand, order, etc. When the main clause has the verb denoting one of the above mentioned meanings, then in subordinate clauses subjunctive is used, i.e. a verb without -s.


Not the answer you're looking for? Browse other questions tagged or ask your own question.