— What's _____ most useful invention in
题型：选择题
问题：
— What's _____ most useful invention in the 20th century?
— _____ computer, I think. [ ]
A. the, A
B. a, A
C. the, The
D. /, The
— What's _____ most useful invention in the 20th century?
— _____ computer, I think. [ ]
A. the, A
B. a, A
C. the, The
D. /, The