Dolly A Winger wrote: This sentence appears in our school newsletter this week: *The use of technology is not an addition to the curriculum, it is a change in how curriculum is delivered. * Could you explain why this sentence and others like it are, evidently, legitimate sentences rather than examples of run on sentences. I see professional authors doing this type of sentence repeatedly, and I'm confused by it. I personally would use a semi-colon rather than a comma just because someone taught me that not joining sentences with commas was a rather basic requirement. Help! <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< In this case, as in many others, we need to look at what the rules are for. Basically, punctuation serves one purpose - to help the reader process the sentence. Like Dolly, if I were writing the sentence, I would use a semicolon, primarily because the semicolon emphasizes the contrast in the ideas. The writer, however, apparently felt (as do, as Dolly notes, many others who use this structure) that readers would have no problem in processing the sentence with a comma. Although technically, this creates a comma-splice, I would not consider it as an error. (Remember that old rule about not being able to join main clauses with a comma UNLESS the clauses were short?) The "is not" in the first main clause raises expectations of "It is," and those are the first two words in the second main clause. Note that, in a sense, the whole second main clause is a negative appositive to the first: *The use of technology is not an addition to the curriculum, it is a change in how curriculum is delivered. *