'I'm not sure,' she responded.

“我不肯定。”她答道。

《牛津词典》

'I'm not sure,' she replied evasively.

“我不敢确定。”她躲躲闪闪地答道。

《牛津词典》

I'm not sure whether I should tell you this.

我拿不准该不该把这事告诉你。

《牛津词典》

I'm not sure. And if the whole world is against the good justice for the suspects of the Rwandan genocide, what next?

VOA: standard.2009.04.10

Answer,I'm not sure.

答案是，我不太确定。

耶鲁公开课 - 死亡课程节选

It kind of depends. Probably like 4 hours a day, 5 hours a day, I'm not sure.

视情况而定。大概每天4，5个小时，我也不太确定。

关于学校生活 - SpeakingMax英语口语达人

But where this Toshiba tablet fits in -- between those devices and the TV -- I'm not sure.

CNN: SHARE THIS

Would she recognise her role in delivering devolution - whether potent player or campaigning tool? i'm not sure.

BBC: Yes for Wales or no to Thatcherism?

Whether he can count on them under these circumstances, I'm not sure.

CNN: SHARE THIS