水非常深，她见不到底。

The water was very deep and she could not see the bottom.

youdao

掉啊，掉啊，掉啊，难道永远掉不到底了吗？

Down, down, down. Would the fall NEVER come to an end!

youdao

大鹏鸟飞得很高，根本看不到底下地面的情形。

The roc flew so high that I couldn't see the earth below me.

youdao

The problems that Frost poses are problems of interpretation, - problems that provoke you to ask not, "what does he mean exactly?

弗罗斯特给我们的困难是翻译，是使人不发问这样的问题，“他到底要说什么“

耶鲁公开课 - 现代诗歌课程节选

I don't know, I didn't go to business school so I'm not exactly sure how it works.

我不知道，我没在商学院上过学，所以我也不清楚它到底是怎样的。

哥伦比亚的氛围 - SpeakingMax英语口语达人

I mean, I don't know, I don't know the criticism... Yeah, I think they would say that.

别介意，我也不知道到底会面临什么样的批评。。。,是的，我觉得会有人这么说。

普林斯顿公开课 - 人性课程节选