An opinion is your belief about a topic(i.e politics) an assumption, is what you think about a topic. A fact is common knowledge, like something that was proven by science( the sun is a star)
The clause <em>who bought the coat </em>is used as an adjective subordinate clause because it modifies the noun <em>the man. </em>What man forgot his umbrella? (The one) who bought the coat.<em> </em>
