https://ell.stackexchange.com/a/164712/35099 ,@djna taught me about non-restrictive relative clause. Now I meet a more complex one: Spark acquires executors on nodes in the cluster, which are processes that run computations and store data for your application. How can I justify which part the clause modify? executors,nodes or cluster?I can tell from my knowledge it's "excutors". But any syntax rule can I use to judge?

  • I view this sentence as badly formed; as @joiedevivire has explained breaking into two sentences greatly improves clarity. I would not expect technical documents to be models of good writing. As a former IT person I'm all too aware of my own inability to write clearly and grammatically - it's hard enough getting the technical aspects right.
    – djna
    May 1, 2018 at 7:09
  • It doesn't modify anything. Non-restrictive relatives are not modifiers but supplements. They have an antecedent of course, called an 'anchor', which they refer to, but do modify. The semantic anchor can be anything you like, but you still need it to be unambiguous, which it is here. Since the verb is the plural "are", it could be any one of the plural NPs: "nodes in the cluster", "executors" or the larger NP "executors on nodes in the cluster".
    – BillJ
    May 1, 2018 at 7:14
  • thanks,at least I know it's not always my fault to be trapped by these ambiguous
    – yuxh
    May 1, 2018 at 8:17
  • @djna ,does "the most recent noun" rule not always right?What's the condition this rule not apply?
    – yuxh
    May 1, 2018 at 8:24
  • It only applies when the author adheres to the rule :-) Here, I claim, the author does not follow normal sentence structure. As readers we use the thought process outlined by joiedevivre and understand the intention.
    – djna
    May 1, 2018 at 9:09

1 Answer 1


For maximum clarity, you might consider just breaking it into two sentences:

Spark acquires executors on nodes in the cluster. Executors are processes that run computation and store data for your application.

The "rule" is that the "which" clause modifies the most recent noun in the sentence. So grammatically, it sort of modifies "cluster." However, your audience will rule out "cluster," because the verb conjugation "are" doesn't agree with it. (It's legitimate to use conjugation to skip referents this way.)

That means the audience will skip backward to "nodes." Assuming your audience is even a little bit technical, they'll know the "which" clause probably isn't defining nodes, either, and if they parse fast enough and remember the word "executors," they'll know that executors are what you're talking about. Still, it's best to avoid all that pain and ambiguity by just making two sentences.

  • 1
    Yes, but non-restrictive relative clauses are not modifiers -- they are not a dependent of the head noun, i.e. they do not combine with the antecedent to form a syntactic constituent as happens with restrictive relatives.
    – BillJ
    May 1, 2018 at 7:19
  • @BillJ Thank you, as always, for the technical definitions. I really do enjoy reading and learning from what you say. However, I don't think it substantially changes the logic required to parse which is the "anchor NP" if I change the terms I used in my answer. I do see a point that maybe "the most recent noun" isn't the rule. But I think English-speaking humans still probably parse nouns and NPs in reverse order to find the logical fit. Am I mistaken? May 1, 2018 at 7:33

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