Ответ:

Insert prepositions or post-verbal adverbs:

  1. If it is not the person you want to speak to, please ask to call the one you want.
  2. Do you have enough time for me?
  3. We should better discuss this matter over the telephone.
  4. Even if your friend is angry, never answer back. Keep your emotions to yourself.
  5. Telephone unites people, but it should be used carefully not to separate them.