44. A. unnecessary
B. useless
C. random
D. impolite
45. A. concern
B. worry
C. ponder
D. determine
46. A. Often
B. Seldom
C. Always
D. Still
47. A. doubt
B. meaning
C. reason
D. time
48. A. return
B. devote
C. lead
D. proceed
49. A. result
B. solution
C. distinction
D. resolution
50. A. while
B. as
C. since that
D. so that