The problems at the meeting tomorrow are really hard to solve.
A. discussed
B. to discuss
C. to be discussed
D. discussing
网友回答
A. discussed
B. to discuss
(答案→)C. to be discussed
D. discussing
解析:The problems 与discuss之间是被动的关系,应用被动语态;tomorrow这个时间状语决定应该是将来的事情,不定式可以表示将来,因此选C。