We often omit relative pronouns in restrictive clauses. E.g. "I am flying to a place I love" instead of "I am flying to a place that I love."

It seems ok to omit the which/who in the following. But what are rules for omitting relative pronouns for non-restrictive clauses?

The treatment, which was covered by insurance, lasted days.

The treatment, covered by insurance, lasted days.

John, who was buried in debt, sold his house.

John, buried in debt, sold his house.

  • 4
    This is an example of Whiz-Deletion, which deletes a relative pronoun subject and an immediately following auxiliary form of be, thereby converting relative clauses with progressive, passive, or nonverbal predicate constructions into participial phrases. Whiz deletion works on both restrictive and non-restrictive relatives; with predicate nouns and non-restrictive clauses, it creates appositive noun phrases. Commented Dec 18, 2014 at 0:02
  • 1
    The versions without relative pronouns arguably parse better as participial phrases than as relative clauses: that is, the elision may be of the participle being rather than of the relative pronoun. This parsing may tend to imply more of a causative relation. (And it is alas true enough that insurance coverage often causes treatments to last longer.) Commented Dec 18, 2014 at 0:04
  • It's the difference between saying "John, who married Susan, sold his house." and "John, having married Susan, sold his house." The latter implies that the marriage led to the sale of the house, whereas the former is ambiguous in this regard. Commented Dec 18, 2014 at 0:43
  • Based on the comments, it seems that if emdash is used to separate out the non-restrictive (descriptive) clause without relative pronoun, then that'd do the trick. That is, it would not be ambiguous regarding whether it's participial phrase or non-restrictive clause. So the setences would become "The treatment--covered by insurance--lasted days" and "John--buried in debt--sold his house". Would this punctuation retain the non-restrictive meaning while also being perfectly fine for formal writing?
    – Joe Black
    Commented Dec 18, 2014 at 5:17

1 Answer 1


In your examples, ALL the nonrestrictive clauses tell us something about the subject of the sentence without foreclosing the possibility of other subjects fulfilling the predicate of the sentence. They ALL conform to the rule of non-restrictive clauses.

The difference between your pairs seems to be the emphasis. Using the relative pronoun tends to add emphasis to the identity (treatment or John), while omitting the relative pronoun tends to leave the emphasis on the condition (covered or buried). Technically, this seems to be a matter of style rather than grammar.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

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