过去经常,曾经;
例句:
Hearts and flowers don't do as much for girls as they used to.
现在的女孩子并不像过去的女孩子那样多愁善感.
You used to see a lot of her, didn't you?
你过去常见她吧?
There used to be a large car park on this site.
这地方曾经是个大停车场。