Not only the supply of mahogany has dwindled markedly in the past ten years , but its price has tripled during the same period of time.
A.the supply of mahogany has
B.markedly
C.but its
D.price has tripled

 Provide pensions for retired people is the primary function of the social security system.
A.Provide 
B.pensions 
C.retired 
D.the primary function

The  Girl Scouts , found by Juliette Gordon Low in 1912 , has grown to a current membership of more thanthree million girls.
A.Found  
B.in 1912
C.has grown     
D.more than

When I came back , I realized that my camera had been disappeared .
A.came back
B.realized
C.my camera
D.had been disappeared

What we know about certain diseases are still not sufficient to prevent to prevent them from spreading easily among the population. 
A.What we know about
B.Are 
C.From spreading
D.Among

______(57)
A.preconception 
B.knowledge 
C.understanding 
D.feeling

______(56)
A.quantity
B. quality
C.effect 
D. product

______(55)
A.integral
B.mixed
C.fractional
D.superior

He inherited a lucrative business from his father.
A.lucid 
B.profitable
C.wealthy
D.losing

Dr.Jones suggested that final examinations should be discontinued , an innovation I heartily support.
A. Inner part 
B. test
C.change 
D.entrance