他心中充滿了憂愁，不知道該如何面對未來。
His heart was full of sorrow, not knowing how to face the future.
Listen to pronunciation
Example sentences
我不知道他什麼時候會回來。
我不知道他什么时候会回来。
I don't know when he will come back.
他盯著窗外發愣，不知道在想什麼。
He stared out the window in a daze, not knowing what he was thinking.
Usage Notes
A very common phrase used to express a lack of knowledge or awareness about something.
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