Replying

The President did me the courtesy of replying to my letter.

I'm sorry I'm late replying to your email.

I apologize for not replying right away.

I apologize for the delay in replying.

Tom didn't even bother replying.

I'm sorry for not replying to your letter earlier.

I'm sorry for not replying to your email earlier.

Tom waited a moment before replying.

Why did she stop replying to me?

Could you do me the courtesy of replying?