Can I say,<br/><br/>(a) He is crying because his knee is hurt.<br/><br/>(b) He is crying because he hurts his knee.<br/><br/>(c) He is crying because his knee is bleeding.<br/><br/>(d) He is crying because he hurt his knee. (He hurt his knee first, so I use "hurt" in past tense,but I'm talking the boy now. Am I right? ) <br/><br/>(e) He is crying because his knee was hurt. ( The reason is same like above sentence)