In the following part of the lesson
Note that with the following expressions of opinion, the mode of the following verb changes whether the opinion is expressed in an affirmative or negative form (using negative structures like ne...pas etc).
I believe the addition of "in accordance with" between "changes" and "whether" would obviate listening for "or not", which does not appear, and thereby throwing off the student. Alas, it through me. Thus rephrased text would therefore be
Note that with the following expressions of opinion, the mode of the following verb changes IN ACCORDANCE WITH whether the opinion is expressed in an affirmative or negative form (using negative structures like ne...pas etc).