In the following sentence, which verb is right?

A century of discoveries in genetics ( has / have ) unlocked the secrets of our DNA.

  • 2
    This kind of question is a common stumbling block. Hint: What noun is the subject of the verb unlock? Compare to this—What form of the verb weigh would you use in This bag of rocks ___ a lot? Oct 12, 2023 at 10:45
  • 3
    Native speakers are split on this. Some use the singular with century and others would use the plural with discoveries. century is the grammatical subject in old-school grammar. But I think many editors nowadays would let either form pass. Oct 12, 2023 at 10:46
  • I agree with @TimR. But note that it can be very dependent on context. I doubt that even the most nowadays of editors would accept *This bag of rocks weigh a lot. Oct 12, 2023 at 11:04
  • I think most editors would play it safe and swap problematic plural discoveries to research or similar. Google Books has 3-4 different instances of singular A century of discoveries has..., and no hits at all for plural A century of discoveries have... But there are shedloads of hits for a century of research has... Oct 12, 2023 at 13:43
  • ...essentially, if there's a usage where native speakers who regularly interact with each other have different preferences, there's usually a tendency to find alternative phrasing rather than try to find out which version your boss prefers (so he doesn't pigeonhole you as "ignorant", and therefore not worthy of a pay rise! :) Oct 12, 2023 at 13:48

2 Answers 2



The subject of the sentence is "century." You must make it agree.

If you wanted to rephrase it, it could be

A century's discoveries in genetics have unlocked the secrets of our DNA.


Over the last century, discoveries in genetics have unlocked the secrets of our DNA.

But it would have to be rephrased.


I think you can go either way, depending on where you want the emphasis.

If you consider the subject of the sentence to be a century of discoveries, that's a singlular subject and you would say has. Here the emphasis is on the period of time during which people made new discoveries.

If you consider the subject off the sentence to be discoveries, that's plural and you would say have. Here the emphasis would be on the discoveries themselves.

  • The head of the subject NP can only be "century". Only with certain non-count quantificational nouns like "lot" and "plenty" does the number of the complement of "of" determine the number of the whole NP.
    – BillJ
    Oct 13, 2023 at 8:05
  • 1
    @BillJ: You don't consider century to be analyzable as such a non-count quantificational noun? Oct 13, 2023 at 12:20
  • The Guardian has no problem with it: "A century of readers have reached for the same adjective." A scientific article says: "A decade of collaborative efforts have led to remarkable innovations". This page says "I hope that these more than a decade of friendship quotes have inspired you." So it seems many speakers are happy to use it this way.
    – nschneid
    Oct 14, 2023 at 19:29

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .