我不小心删除了文件。

I deleted the file ___by ___accident.

我在跳舞时，有人不小心踢到了我，我的眼镜掉了下来。

I was dancing and someone kicked me ___by ___accident, and my glasses fell off.

她不小心把牛奶洒了。

She spilled the milk ___by ___accident.