<p>An experimental accident in London led to the discovery of penicillin “in the 1920s, when Alexander Fleming learned” of the mold’s curative properties.</p>
<p>Should there be a comma before “when?” This was on a McGraw Hill Test and there are errors on the tests. I am not sure if this is one or not.</p>
<p>Commas are not tested on the SAT, so you shouldn’t worry too much about them.</p>
<p>I believe there should be a comma before “when.”</p>
<p>@ EssayTees,</p>
<p>Actually there was a comma splice problems in the SAT Question of the Days</p>
<p>Yes, comma splices are tested on the SAT. All of these questions contain two independent clauses separated by a comma. It’s a problem of sentence structure, rather than where to place the comma in a sentence. Questions like the one here, where the original poster is asking whether or not there is a comma, are not tested.</p>