1·Are you sure about that?
这事你肯定吗？
—— 《牛津词典》
2·I'm not sure about it .
我对这不确定。
3·The interviewer may think you are not sure about your ability.
面试官可能会认为你对自己的能力没有把握。
4·If we humans aren't quite sure about a decision, we go and ask somebody else.
如果我们人类对一个决定不是很确定，就会去问其他人。
5·When people are having a picnic, but it begins to rain, they will be so sure about something that shows the weather is going to be fine very quickly.
当人们正在野餐，但开始下雨时，他们会非常肯定地认为天气会很快好起来。
6·In general, these "short sleeps" appeared ambitious, active, energetic, cheerful, conformis in their opinions, and very sure about their career choices.
总的来说，这些“短睡眠”的人表现出雄心勃勃、积极向上、精力充沛、性格开朗，对自己的职业选择非常自信。
7·In general, these "short sleeps" appeared ambitious, active, energetic, cheerful, conformist in their opinions, and very sure about their career choices.
总的来说，这些“短睡眠”的人显得雄心勃勃、积极向上、精力充沛、性格开朗，对自己的职业选择信心满满。
8·'I'm not sure about it,' he said weakly.
“这我说不准。”他支吾说。
—— 《牛津词典》
9·He was sure about his future school life now.
他现在对未来的学校生活十分有把握。
10·I'm not sure about the exact date but I totally agree.
我不确定具体日期，但我完全同意。