I read the sentence

The driver process runs your main() function, sits on a node in the cluster, and is responsible for three things:...

I am not sure

sits on a node in the cluster

modify the process or function . I always stumble by the similar situation, please tell me how I can call this syntax and what's the rule to judge this?

1 Answer 1


The key is to look for a relative pronoun such as which.

We are comparing these two patterns

The X is a, b, and c

The X is a, which b

In your example you are asking how we know that "sits ..." tells us more about process rather than your main function.

In technical terminology you are asking how we can identify a non-restrictive relative clause. The two identifiers are

  1. a preceding comma
  2. the use of which (or other relative pronouns such as who)

The driver process runs your main() function, sits on a node in the cluster

No which, so we are learning more about the driver process

The driver process runs your main() function, which you have developed

Here we have a which. So this is a non-restrictive relative clause, which gives us more information about the main() function.

For comparison, there is also the possibility of a restrictive relative clause. This has no preceding comma and often uses that. A restrictive clause is essential to the meaning of the sentence.

Rugby is a game that is played with an oval ball.

There are some differences between US and UK uses of that and which and you can read more about this in articles such as this one.

  • I am confused by two identifiers in your description, The two identifiers means non-restrictive relative clause. My example apply identifier 1, your example apply identifier 2, but why have different meaning?
    – yuxh
    Apr 26, 2018 at 8:10
  • My example applies both identifiers: the comma and the "which". Your example does not have "which", so it is not a "non-restrictive relative clause". It's the which: "The X is a, which b" is the pattern that links b to a, not to X.
    – djna
    Apr 26, 2018 at 9:12
  • thanks, so your two identifiers are "and" relation to constitute "non-restrictive relative clause"? I thought wrong as "or" relation.
    – yuxh
    Apr 27, 2018 at 8:59
  • BTW,could you tell me my original sentence's technical terminology?
    – yuxh
    Apr 27, 2018 at 9:07
  • Yes and not or. I'm not confident of the terminology, but I think you have a sequence of non-restrictive clauses. You could remove either "runs your main() function" or "sits on a node in the cluster" and the sentence would be well formed and understandable; though it would lose information it is still grammatically correct.
    – djna
    Apr 27, 2018 at 11:30

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