A.off-spring
B.ancestors
C.pioneers
D.juniors

A.Historians
B.Inspectors
C.Advocates
D.Experts

A.theaters
B.attends
C.shifts
D.authors

A.evolve
B.protection
C.operate
D.robot

A.Otherwise
B.However
C.Therefore
D.Moreover

A.determined
B.communicated
C.dominated
D.indicated

A.has became
B.one of
C.most serious
D.social problems

A.has became
B.one of
C.most serious
D.social problems

A.To grow
B.a tree
C.well-suited
D.it was

A.enjoys listening
B.the works
C.classic composers
D.is studying