Um, I'm not sure how to ask you this...

嗯，我不知该怎么问你这个…

《牛津词典》

"Listen and comment appropriately and be sure to avoid phrases such as' um, ' 'you know,' and 'like,'" she said.

“倾听对方，并适当发表意见，但一定要注意，避免用‘哦……’、‘你知道的……’、‘好像’之类的口头语”，她说。

youdao

Other times I hear a confused "Um, I'm really not sure what you mean."

另一些时候，我会听到迷惑的回答：“我不明白你的意思。”

youdao

Oh, man. Um, I'm not 100% sure what I want to do as far as careers go.

天啊，就未来的职业来说，我还没有百分百的打算。

汉语学习课程很难 - SpeakingMax英语口语达人

Yeah, I, to be honest, I'm not sure that's so true. Um...

是，我，实话说，我不知道这是不是真的。呃…

对于赞助入学的看法 - SpeakingMax英语口语达人

One thing I know for sure, even though the IDPs in these small camps - Um Labasa has only 426 IDPs - do not have the same level of services as the IDPs in the big and more accessible camps they seem to be more content with what they have.

BBC: NEWS | Africa | Darfur aid worker's diary XVII