1. ---I’ve bought a box of chocolates for our daughter.
  ---Oh, how good a dad! But she doesn’t like sweet things, _____that?
 A. Don’t you know              B. Haven’t you known  
 C. Didn’t you know              D. Hadn’t you known
2. ---Have you decided already?---Yes, I ____at once.
 A. have decided   B. decided  C. will decide   D. had decided
3. Glad to see you back. How long _____in Russia?
 A. did you stay  B. have you stayed  C. were you staying  D. have you been staying