If you did something in the past but you no longer do it now, you can use the verb phrase . . used to . . / . . used to . . e.g.

如果你在过去做某事但是你现在不做了，你可以用动词短语. . used to .

youdao

That's not something I normally do. I probably used to when I was a lot younger, but my life's very busy now.

我通常不玩什么游戏。我过去小的时候可能玩，但是现在我们生活太忙碌了。

youdao

It originally means the misoperation due to carelessness and now is used to describe a person do something deliberately but argue that he has done it unintentionally.

本意指因粗心大意而造成操作失误。现被用为，故意做的，却说是失误造成的。

youdao

Before now it was not clear whether the bacteria directly conducted an electrical charge themselves or used something else to do it.

BBC: Bacteria power 'bio-battery' breakthrough