He was ______ medical student before he turned _______ engineer.
52. The two American came to China for a visit. They visited many places ______ and enjoyed themselves.
51. In the low latitude area, it is usually very _____ all the year around.
50. Teachers should be _____ with their students but should not be _____ on them.
49. Western people usually say “_____ New Year and _____ Christmas.”
48. When the _____ young actor appeared on the stage, all eyes were fixed upon him.