Which one is the correct one?

I had no idea San Diego (and its surrounding areas) is that crowded.


I had no idea San Diego (and its surrounding areas) are that crowded.

And would the answer be different if I used commas instead of the two parentheses?

  • 1
    This question is very similar to Changing plurality in parentheses -- does that question give any pointers?
    – Andrew Leach
    Feb 28, 2013 at 8:21
  • 3
    No, because all the commas do is define a parenthetical phrase. That particular sentence doesn't really need brackets or commas: just run it all together [and use are].
    – Andrew Leach
    Feb 28, 2013 at 8:34
  • 1
    I think there are questions I've never seen addressed, here or hereabouts. The standard mantra is 'a parenthesis must be deletable with no resulting ungrammaticality' (though I've not come across whether this applies to comma-enclosed and dash-enclosed parentheses as well as to parenthesis-enclosed parentheses). However, what restrictions are there on the nature of the parenthesis? This can be wildly at odds with the matrix sentence { Bob (what muscles) floored Ted. Joe (no kidding) bottled it. Sam (!) ran off.} But San Diego (and its surrounding areas) is busy. does seem wrong. Feb 28, 2013 at 23:50
  • 2
    Roronoa: this problem has been buzzing round my bonnet. (1) I agree that the use of brackets gives a different emphasis, and rewrites without them lose that. (2) Even though parentheses are supposed to be syntactically independent of the matrix sentence, I agree with you that I had no idea San Diego (and its surrounding areas) is that crowded. sounds 'off'. (3) A rewrite preserving the 'afterthought' nuance (assuming that is the purpose of the use of the parenthesis) is: I had no idea that San Diego was that crowded (as, apparently, are its surrounding areas). Mar 1, 2013 at 9:22
  • 1
    @EdwinAshworth: Late response: you may find Byron's answer to english.stackexchange.com/questions/403708/… interesting; he seems to have found sources that address this exact issue.
    – herisson
    Aug 1, 2017 at 3:52

1 Answer 1


As Andrew has said in his comment, you don’t need brackets here. By using them you create an unnecessary difficulty, and you don’t really need to replace them with commas. San Diego and its surrounding areas is a plural subject, so it needs a plural verb.

What you also need is the verb in a different tense. The second clause in the sentence is, in functional grammar terms, a projected clause. That is, it is similar to indirect speech, in which present tenses normally become past tenses. All these considerations point to writing the sentence as:

I had no idea San Diego and its surrounding areas were that crowded.

  • This does not convey the 'afterthought' idea, which the author may want to. Aug 1, 2017 at 8:52

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