Personal computers _______ in 1976. It h
题型:选择题
问题:
Personal computers _______ in 1976. It has changed the whole world. [ ]
A. have been invented
B. are invented
C. were invented
D. invented
Personal computers _______ in 1976. It has changed the whole world. [ ]
A. have been invented
B. are invented
C. were invented
D. invented