she has been in hospital since she was shot on the head 为什么要用since不能用after
问题描述：
she has been in hospital since she was shot on the head 为什么要用since不能用after
除了前面是现在完成时这个理由
答
she was shot on the head 是个状态 头部中枪
after 之后跟一个动作即 she got a shot on the head