根据句意及首字母的提示，补全单词。
1. Jim h_____ his knee when he played basketball.
2. I f_____ off the bike and had a pain in my leg.
3. —What is the m_____ with your finger?
    —I cut it by accident.
4. I had p_____ seeing the blackboard. Maybe I am short-sighted.
5. I saw an a_____ on my way here.  A car hit a bus.