didn't know what to do
I didn't know what to do, so I called the police.
They didn't know where to go.
私は彼の思いがけない質問にどう答えたらよいかわからなかった。
I didn't know how to answer his unexpected question.
I didn't know what I should do first.
I didn't know what to say, so I kept quiet.
I was at a loss because I didn’t know what to do.
I didn't know what to say, so I kept quiet.
I didn't know how to answer his question.