No guide sufficiently teaches you when to drop certain terms in parallelism.
I've looked everywhere, and no guide really explains it well. The only OK one is in MGMAT SC book, which says that you need to repeat the front terms if there is a closed parallel marker. Example: not in x but also in y. --> IN MUST be repeated. In open markers, it's not clear. Consider the following incorrect sentence: The discovery that Earth’s inner core rotates independently of and more quickly than Earth’s outer layers is responsible for advancing studies of how heat from the inner core flows through the outer planet, and the formation and periodic reversal in direction of Earth’s magnetic field This is wrong because there is no second OF: studies OF how heat... and OF the formation.. would be correct. How the heck am I supposed to know what to drop and what to not put? MGMAT SC says to replace an element in front of the start to see if it makes sense. The discovery that Earth’s inner core rotates independently of and more quickly than Earth’s outer layers is responsible for advancing studies of the formation and periodic reversal in direction of Earth’s magnetic field. This makes sense, so why does OF need to be repeated again? Why can't the OF be distributed to both? The most frustrating part is that no guide really tells you exactly what should be done. Everybody just says "needs OF because of parallelism". But in many cases, the front part can be dropped and still be parallel. So when exactly can you drop and when can you not? I thought this one was OK because the sentence completely makes sense if I put the second element in front of the first OF, so OF can be distributed.