Our environment will be worse and worse unless something_______.A.was done B.is doneOur environment will be worse and worse unless something_______.A.was done B.is done C.will be done D.to be done
问题描述：
Our environment will be worse and worse unless something_______.A.was done B.is done
Our environment will be worse and worse unless something_______.
A.was done B.is done C.will be done D.to be done
答
选B
从句用一般现在时