walk a dog
Did you walk a dog yesterday? Yes, I did. I walked a dog. / No, I didn't. I didn't walk a dog.
tidy your room
Did you tidy your room yesterday? Yes, I did. I tidied my room. / No, I didn't. I didn't tidy my room.
surf the Internet
Did you surf the Internet yesterday? Yes, I did. I surfed the Internet. / No, I didn't. I didn't surf the Internet.