while we saw an old man fell off his bike----when we saw an old man fell off his bike（see是短暂性动词,不能用while引导这个时间状语从句.）
carrying an old man ---carrying the old man
to hospital---to a hospital(hospital表示抽象的概念时才不用冠词）
He has learnt first aid ---He had learnt first aid（过去的事不能用现在完成时,因为现在完成时强调现在）
At this time---At that time
called in--called up
the old man's breathing---the old man's breath
use the mouth-to-mouth way---using the mouth-to-mouth way(现在分词作伴随状语）
or doctors also arrived--and doctors also arrived
that we had done---what we had done (引导宾语从句时,that不能同时在从句中作主语或宾语.而what可以.）
另外,so she said that可能是抄错了吧,应当是so he said that.