I sent a postcard to my friend.

Could you tell me your postal code?

I sent you a postcard.

I sent important documents by registered mail.

There is not a single letter in my mailbox.

Please put the letter in the post office box.

I posted a letter in the mailbox.

My borborygmus was so loud that everyone could hear it during the meeting.

I found a crying rabbit in the park.

I found a nakiusagi in the park.