他说，他不完全确定自己会选择做什么。

He has said that he isn't exactly sure what he will choose to do.

youdao

科学家们也不能完全确定，他们有不同的想法。

Scientists aren't completely sure, and they have diverse ideas.

youdao

虽然我不完全确定，但我认为咖啡豆来自巴西。

I think the coffee beans are from Brazil, though I'm not completely sure.

youdao

We need to think that the actions in the story were in some way free and absolutely, perfectly undetermined.

得让读者以为故事中角色的所作所为某种程度上,都是自由的，完全不是事先确定的。

耶鲁公开课 - 弥尔顿课程节选

You know, speak even if you're not sure exactly what you're saying is totally correct,

即使你不能确定你讲的内容是否完全正确，你也要开口讲出来，

想学好英语吗？ - SpeakingMax英语口语达人

So now we're just counting up our orbitals, an orbital is completely described by the 3 quantum numbers.

所以现在我们只要把这些轨道加起来，一个轨道是由３个量子数完全确定的。

麻省理工公开课 - 化学原理课程节选