介绍:
a sure thing: 十分有把握的事情，肯定会发生的事情，确定的事情，主语也可以是人。
A is a sure thing. A这件事儿没问题，肯定的，妥妥的
B is not a sure thing. B这事儿还没有最终确定。
Gary很有可能被哈佛录取，但还没有最终确定。
Gary has a good chance of getting into Harvard, but it's not a sure thing.
Nicole在竞选学生会主席，她觉得自己肯定没问题。
Nicole is running for the the president of the Student Union, and she thinks she's a sure thing.
没有什么事情是百分百肯定的。
Nothing is a sure thing.
