The precise answers for this would presumably relate back to the specific semantic features you've discussed in your class. Having said that, my guesses for the above 3 would be as follows:
#The Giraffe broke - Semantic Feature: +Animate . Explanation: Things that are "alive" do not "break" in the physical sense of the word. You can break a chair, or a cup, but it'd be weird to say you "broke a dog".
#Boulders dripped all over the road - Semantic Feature: +Solid?? (This one I was most unsure of). Explanation: Dripping seems like something associated very much with being a "liquid" state of matter. I struggle to find solids or gases that I would describe as "dripping".
#The bicycle is afraid of the dark - Semantic Feature: -Animate. Explanation: Things that aren't alive do not feel fear in any conventional sense of the word.