Whenever I encounter a double negative that gives me trouble, I rephrase it in my own words. PT46.S2.Q10 is a good example of this. You can rephrase "X is not indispensable" to "X is not essential."
In Prep-Test 76 the system scored me wrong on S1 Q18, when my answer matches the solution table supplied with the prep-test and other online resources.
I simply do not understand how the answer choice parallels the stimulus at all. Can anyone explain it to me to help me understand? Thank you! PT8.S1.Q16.