问题
选择题
When _____ the telephone _____ ? [ ]
A. did ; invent
B. was ; invented
C. was ; inventing
D. does ; invent
答案
答案:B
When _____ the telephone _____ ? [ ]
A. did ; invent
B. was ; invented
C. was ; inventing
D. does ; invent
答案:B