题目

When Mike Mushaw decided to join the national bone marrow registry (骨髓登记) nearly three years ago, he never really gave it a second thought. After all, he did it only because his college football coach had _______ him and his teammates to register.About six months after the registry, Mushaw got a call. His bone marrow matched a _______ in Virginia. Mushaw didn’t know it at the time that his marrow would _______ to a five-month-old girl named Eleanor with a rare _______. She had hardly _______ her house, and the only place she went to was the _______ because her immune (免疫的) syst化简求值5a+3b﹣2（3a2﹣3a2b）+3（a2﹣2a2b﹣2），其中a=﹣1，b=2．