Data did not reply immediately because he was too stunned to speak.

She did not immediately reply, feeling that to continue to do so was to play to his own interests.

He didn't reply immediately, and for a moment Pamela thought she'd lost him again.

When I did not reply immediately, she pulled her hand away.

Troy was going to reply immediately, but he stopped himself.

She wrote to him, he replied immediately and they quickly exchanged important information.

He did not reply immediately, but sat looking from one to another of these things with growing attention.

And when she didn't immediately reply but held on to his hand for support, he quickly said, "I'll tell her to leave."

So if you reply immediately we will not have heard part of the question.

None of the others with him in the room replied immediately.