be sure about

基本解释

However, you need to be sure about no reuse.
但是，需要确保没有重用。
That is scary, and we cannot be sure about changes in the future.
这是可怕的，因为我们无法确定未来会发生什么变化。
There were many I didn't know, and others I couldn't be sure about because they were so covered in green parasites.
这里有许多我不认识的树，还有有一些树我没法确认，因为它们都覆盖在了密密麻麻的绿色藤蔓植物下。

But Professor Bedau says that nobody can be sure about the results of making new forms of life.
I'm not at all sure there's anything more to be said about that passage, which I think lays it to rest.
我不确定这篇文章是不是,还要更多的讲解，就这样的吧。
耶鲁公开课 - 文学理论导论课程节选
Weird things, bad things can happen and so one of the lessons too that will be repeated throughout the course is to actually rigorously error check and make sure that you're always thinking about your user being a bad guy.
各种古怪的事情就会蜂拥而至,所以在这个课程中我反复强调,要一丝不苟地检查错误,你就当你的用户是个调皮捣蛋的家伙。
哈佛公开课 - 计算机科学课程节选

How can voters be sure about what Republicans really believe, other than the importance of winning elections?
FORBES: Republicans Need To Grow Up About Taxes