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。
The business stakeholders will not be sure about some requirements.
业务利益干系人将无法确定某些要求。
Know your objectives, and be sure about what you're hoping to achieve.
知道自己的目标，并确定您希望得到什么。