What is the difference between these two sentences: (adjective x adverb) I was doing an online english test and I had to answer these two questions, actually I had to complete these questions: 1) He's a very bad driver. He drives very .... a) dangerously (According to site this is the right answer) b) dangerous c) bad ( I selected this one, but the site said it's wrong) 2) And he's a fast driver. Yes, he drives very .... a) faster b) fastly c) fast (Following the same logical I selected the adjective and the site said I was right) For me, those questions sound as the opposite from each other, so why can't the both be answered just with an adverb or just an adjective? Why do I have to answer the first with an adverb and the second with an adjective? Is there a tip to help me identify when I have to use each one? Or is the website wrong?