确定的英文短语：
be sure of、make sure；例如：Be sure to make copies of all the papers.
So we can be sure of the quality.
这样我们才能确保产品质量。
They could not always be sure of that.
他们也许并非总是有把握这样看的。
You could not be sure of winning that time.
那一次你可不一定能取胜。
温馨提示：
