I bought toothpaste during a buy-one-get-one-free sale .

我在买一送一的特价时买了牙膏。

Mr. Adams: And if they really are selling a buy-one-get-one-free ticket, we should definitely pay for the tickets immediately.

亚当斯先生：如果他们真的有买一送一的机票，我们务必要立刻付钱买机票。