拿不准

wǒ ná bu zhǔn yīng gāi rú hé huí dá zhè ge wèn tí

我拿不准应该如何回答这个问题。

I was unsure how to reply to this question.

wǒ ná bu zhǔn gāi bù gāi bǎ zhè shì gào su nǐ

我拿不准该不该把这事告诉你。

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