20. ---- It looks heavy. Can I give you a hand.　 ----- _________

　 A. Yes, I do.　 B. Yes, my pleasure　 C, No, never mind　　 D. No, thanks.

19. ---- I am sorry, I _______ at you the other day.

　 ---- Forget it. I was a bit out of control myself.

A. shouldn’t shout　 B shouldn’t have shouted　 C. mustn’t shout　　 D. mustn’t have shouted