In those days, books _____ one at a time
题型:选择题
问题:
In those days, books _____ one at a time by hand. [ ]
A. should be produced
B. should be produce
C. could be produced
D. could produce
In those days, books _____ one at a time by hand. [ ]
A. should be produced
B. should be produce
C. could be produced
D. could produce