48. Sometimes they _____ their students' poor comprehension to a lack of intelligence.
A) attribute
B) assign
C) attach
D) associate
49. To _____ greater accuracy, all invoices will be double-checked before leaving the office.
A) assure
B) ensure
C) insure
D) ascertain
50. As a natural body substance, interferon (干扰素) has few side _____.
A) influences
B) effects
C) impacts
D) functions
51. The police _____ together all they had found out about the wanted man.
A) combined
B) mixed
C) pieced
D) joined
52. When Bob came in, Jean _____ her talk with Linda and talked to Bob.
A) broke off
B) cleared away
C) cut across
D) set apart
53. Foreign mutton is _____ to home-grown in flavor.
A) worse
B) indifferent
C) inferior
D) subordinate