【题目】The plan was that the two companies should first reach an agreement on the basic principle, the details _____ later.
A.to be discussed
B.discussed
C.were discussed
D.discussing

【答案】A
【解析】句意：计划是两个公司应该就基本原则达成协议，细节以后商谈。从句中的逗号可以看出，后半部分不是句子，而是独立主格结构作状语，用动词不定式表示将要发生的动作，discuss和the details之间构成动宾关系，要用被动语态，所以A项正确。故选A。