be with auxiliary do

[do + be + adjective/noun
don’t + be + adjective/noun]

  • Don’t be … is used to give people advice or orders.
      Don’t be afraid. Don’t be a fool!

    In affirmative sentences, we usually just use Be . . .

      Be careful!

    But Do be . . . is used for emphasis.

      Do be careful, please!!!
      Do be quiet, for God’s sake!
  • In other cases, we do not use do with be.
      I am not often lonely, (not I do not often be lonely.)