There is a new problem involved in the popularity of private cars_______ road conditions need to be improved.
A.that B.which C.where D.when
There is a new problem involved in the popularity of private cars_______ road conditions need to be improved.
A.that B.which C.where D.when
A
该句为分隔性同位语从句。that引导同位语从句，作problem的同位语，解释problem的具体内容。