<p>The heat was already <em>overwhelming and lasted a week, which duration made it seem</em> sheer torture.</p>
<p>I don't think there is such a phrase as "which duration."
I've only heard of "whose duration."
Isn't "which duraiton" grammatically erroneous?</p>
<p>Personally, I think that if the writer is trying to say that the week-duration made the heat seem like a torture,
he or she should say "... lasted a week, which made it seem... "; that way, the relatvie pronoun "which" will directly indicate "week," the antecedent. Right?</p>
<p>Collegeboard website tells me that if I do as above, the "which" will have an unclear antecedent.</p>
<p>Can anybody tell me how to correct the sentence?</p>