The problem just to be discussed at the class meeting tomorrow.
A. referred is
B. referred to being
C. referring to is
D. referred to is
网友回答
@@A. referred [email protected]@B. referred to [email protected]@C. referring to [email protected]@(答案)D. referred to is
解析：
本题的关键在于理解句子结构： referred to 在句中作定语，修饰名词the problem,而谓语动词为is， to be discussed是它的表语，be to do表示将来的动作。