21. ---I think we should buy a car so that it will be convenient for us to go to work.
---______, but do you think we have so much money ?
A. You are joking B. Come off it
C. I don’t believe it D. You are dead right
22．Jumping out of _______ airplane at ten thousand feet is quite _______ exciting experience．
A．an; an B．不填; an C．不填; the D．the; the
