#4 is a comparative statement, not a conditional statement so how you approach/set up the "lawgic" is going to abide by slightly different rules. If it was a conditional statement, it would say something along the lines of "No small animals move fast" etc. However, we are comparing the speed of small animals to large animals, thus we cannot slap on the negation rules that we previously learned (ie, some or negation of necessary). Therefore, we have to negate the entire sentence " its not the case that small animals move more rapidly than large animals." Its an easy trap to fall into, but the sentence is not saying that "small animals do not move more rapidly than large animals." Instead, we only know that "its not the case that small animals move more rapidly than large animals." Since its a comparative, we can either proclaim the other value as the "winner" or they can be equal. It seems like a small, minute difference between "large animals move more rapidly than small animals" and "small animals do not move more rapidly than large animals," but since, its a comparative, we only know that large animals move more rapidly.