be sure about的用法及例句

　　That is scary, and we cannot be sure about changes in the future.

　　這是可怕的，因為我們無法確定未來會發生什么變化。

　　The business stakeholders will not be sure about some requirements.

　　業務利益干系人將無法確定某些要求。

　　Know your objectives, and be sure about what you're hoping to achieve.

　　知道自己的目標，并確定您希望得到什么。