根据对话内容,用恰当的单词补全对话.
A:What happened,young man?B:I fell down and got ___ on the head.A:Don't move around.Let me help you.B:Oh,my head is ___ very badly.A:Don't be nervous.Let me ___ it under water,put some medicine on it and put a bandage on it.B:Oh!Now I feel much better.A:Err```How did the accident ___?B:I was helping to set up a lent when it happened.A:Oh,you should be ___ whatever you do.