有一天,我回到家发现窗户碎了。
___One ___day, I came home to find my windows broken.
有一天,我正在读一本有趣的书,这时有人给我打电话。
___One ___day, I was reading an interesting book when someone called me.
有一天,我的狗学会了如何开门。
___One ___day, my dog learned how to open the door.