16. A. had been used B. has been used C. used D. was us...
单项选择题16. A. had been used B. has been used C. used D. was used
17. A. many B. much C. any D. some
18. A. as well B. either C. too D. as well as
19. A. was born B. is born C. were born D. are born
20. A. when B. how C. which D. where
