精英家教網 > 高中英語 > 題目詳情
Such a problem still exists because no adequate measures for preventing it _____ taken in the past.

A. are
B. had
C. were
D. had been.
相關習題

科目：高中英語 來源：專項題 題型：單選題

Such a problem still exists because no adequate measures for preventing it _____ taken in the past.
[     ]
A. are
B. had
C. were
D. had been.

查看答案和解析>>


同步練習冊答案
久久精品免费一区二区视