题目内容
______ that the air conditioners cause so much pollution, I would never have bought one.
A. If I knew B. Did I know C. If I have known D. Had I known
D
练习册系列答案
相关题目
题目内容
______ that the air conditioners cause so much pollution, I would never have bought one.
A. If I knew B. Did I know C. If I have known D. Had I known