A:What happened,young man?
B:I fell down and got [hit ]on the head.
A:Don't move around.Let me help you.
B:Oh,my head is [hurting] very badly.
A:Don't be nervous.Let me [put] 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 [happen]?
B:I was helping to set up a lent when it happened.
A:Oh,you should be [careful] whatever you do.