It was all planned well before today that I can be sure about.

Here I believe that that is subordinating conjunction.

It was all planned well before today; I can be sure about that.

Here I believe that that is pronoun, hence the need for the semicolon to separate the two coordinating clauses.

And are they both right? Please correct me if I am wrong.

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    Wouldn't the first alternative also require a semicolon? Commented Apr 27, 2013 at 15:07
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    @EdwinAshworth surely a comma would be better?
    – terdon
    Commented Apr 27, 2013 at 15:38
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    The punctuation is mentioned in the OP, and punctuation is a valid area for discussion according to the rules of the website - I'd have thought that using a comma here would be an example of a comma-splice. Commented Apr 27, 2013 at 18:45
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    Without punctuation, the first example not only sounds awkward, but it doesn't suggest the same meaning to me: I read “that I can be sure about” as an awkward variant of “as far as I'm aware.” Commented May 1, 2013 at 0:19
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    For the two sentences to have roughly the same meaning you should punctuate the first as: "It was all planned well before today; that I can be sure about." the second sentence has inverted OSV-style word order.
    – Mitch
    Commented Dec 7, 2013 at 20:34

3 Answers 3


The word "that" is used identically in both sentences. Since it is not functioning as a subordinator, and the writer is linking two independent clauses, a semi-colon is required in both cases. Edwin is right: using a comma before "that" would create a run-on.

That said, it doesn't mean that a writer might not chose a comma instead. It only means that, given the rules of formal written English, a semi-colon (or a period) would be the conventional choice.


Edwin Ashworth is correct. In the first sentence, you must join the two independent clauses with a semi-colon (or a comma and a fanboys conjunction). A comma is not sufficient to join two independent clauses.


As John commented, that is a pronoun in each case. The confusion around whether it is a subordinating conjunction most likely stems from other grammar issues in the sentence. Quoting John's comment:

There should be a comma after today in the first one, to emphasize the fact that that is stressed, but it's just a fronted object in apposition with the previous clause. It functions like a conjunction does, to introduce a clause, but so do complementizers and many other constructions, so it's nothing special.

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