The difference is in the title. Must be true questions rely heavily on formallogic and the answer choice must be true. MSS questions do not have to be true, but they must be strongly supported.
And one more question, where can I find a list of terms that I can memorize for these formallogic conditions, (e.g. If/then, if and only if, if but only if, if yet only if, unless, not unless, etc.etc)
@"Jonathan Wang" Would you recommend any other sources to learn formallogic in addition to 7Sage? I love what JY has done here, but I feel like my understanding of why Logic works the way it does is a little insufficient.
@DumbHollywoodActor The Coursera course "Think Again: How to Reason and Argue" may also help you. It doesn't go into a lot of depth on formallogic, but it can help you improve your understanding of arguments.