对于每个问题，他都回答“我不知道”。

To every question, he ___responded "I don't know."

我问她几点了，但她没有回应。

I asked her what the time was, but she didn't ___respond.

警察在几分钟内就能应对紧急情况。

The police ___respond to emergencies in just a few minutes.