一天，我回家发现我的窗户被砸碎了。

___One ___day, I came home to find my windows smashed.

一天，我正在读一本有趣的书，这时有人叫我。

___One ___day, I was reading an interesting book when someone called me.

一天，我在公园遇到了一位老朋友。

___One ___day, I met an old friend in the park.