首页 / 高中英语 / 试题详细
  • 更新 2022-09-03
  • 科目 英语
  • 题型 单选题
  • 难度 容易
  • 浏览 2049

4. People begin to know that most environmental problems exist because necessary  measures for preventing them _______taken in the past.

A.are not B.were not C.hadn't been D.wouldn't be
登录免费查看答案和解析
相关知识点

4.Peoplebegintoknowthatmostenv