Great questions Evidence suggests that something MIGHT be true; proof shows that it IS true. If I know that you were in the same building as a crime, that is evidence that you might be the criminal. If I have video of you killing someone, and 20 eyewitnesses, and your DNA at the crime scene, that is close to proof that you are thee murderer. "On and off" is about STATES like being friends or allies. "Now and then" is about repeatable ACTIONS, like eating a bowl of ice cream. "Bob and Tim are off and on enemies. Right now they are being nice to each other, but yesterday they were fighting." "I'm mostly vegetarian, but I eat chicken now and then." "aware" and "conscious" have several meanings, and many of them overlap. The opposite of "unconscious" is usually "conscious," but sometimes people use "aware." The opposite of "ignorant of" is usually "aware of," but sometimes people use "conscious of." It's complicated. If I support an idea, I think it is a good idea. If I'm a proponent, I try to convince other people it'e a good idea. "highs and lows" and "ups and downs" are almost perfect synonyms. Pick whichever one sounds better to you. If I am convinced of his sincerity, it means that I arrived at that belief after thinking about it: I didn't assume he was sincere the first time I heard him speak. If I say "I am confident in his sincerity," I am just telling you that I don't doubt him NOW, but I'm not telling you anything about how I arrived at that belief.