据我所知

jù wǒ suǒ zhī tā shì tā de zhí nǚ

据我所知，她是她的侄女。

She’s her niece, from what I can gather.

yǒu shuí liú guo yán ma méi yǒu jù wǒ suǒ zhī méi yǒu

有谁留过言吗？没有，据我所知没有。

Has anyone left a message? No, not as far as I know.