"Knocked down an old person" 用英语可以说成 "hit and knocked down an elderly person" 或者 "ran over an elderly person"。这个短语来源于英语中的动词 "knock down" 和形容词 "elderly"。
例句1:
I accidentally hit and knocked down an elderly person while I was driving.
(我开车时不小心撞倒了一位老人。)
例句2:
The driver ran over an elderly person and didn't even stop to check on them.
(驾驶员车撞了一位老人，甚至没有停下来看看他们的情况。)