This stranger heard we were planning for my daughter's fifth birthday,
我們正在為女兒的五歲生日做準備，一個陌生人聽到我們的交談

and volunteered to drop off
自發(fā)提出要放下自己的事情

and set up a commercial bouncy house (that the kids loved)
要幫我們做一個游樂場里的那種充氣彈跳床（孩子們都特別喜歡的那種）

and he wouldn't take a cent in payment or let us help.
他不愿意接受任何報酬，也不用我們幫忙

He just told us to play it forward.
只說讓我們在生日聚會開始之前，可以提前玩一下

I was blown away by his generosity
我為他的慷慨和善良感動不已

and it was a lot of work to set up and pack away
搭建帳篷，收拾工具花費了他很多的時間精力

and he just said he likes knowing that kids had fun.
他說，他只是喜歡孩子們開心玩耍的樣子