“不确定”造句

这一承诺能维持多久还不确定。
It is an open question how long that commitment can last.

南希不确定德克是不是在勾引她。
Nancy wasn't sure if Dirk was making a pass at her.

如果能重新活过，我不确定自己是否愿意做出任何改变。
I doubt I would change anything if I had my time again.