21. People often make________fun of him about his height, which makes________ great difference in his life.
A. a; a B. a; the C. /; a D. the; a
22. ［2012哈尔滨模拟］We________the opportunity to go to France, had it not been for Mary’s help.
A. would have lost B. should lose
C. might lose D. must have lost
23. She was moving out of her old apartment________she suddenly realized that the key to the new apartment wasn’t on her.
A. until B. once C. when D. before
