一个不小心，整个人就掉到地板上了。

One is not careful, the whole person fell into the floor.

youdao

一个不小心跌落人间的天使。

An angel falling down to the earth occasionally.

youdao

然而倒霉的一天降临了，当他再次吊在狮笼上时，一个不小心滑落了。

Then one terrible day when he is dangling over the furious lion he slips and falls.

youdao

I declare a variable called n. I'm not giving it a value yet, so I had better be careful.

我申明一个变量n，我先不给它赋值，所以我最好小心点。

哈佛公开课 - 计算机科学课程节选