Only after they had discussed the matter for a few hours a decision
A. they reached
B. did they reach
C. they reach
D. do they reach
网友回答
A. they reached
(答案→)B. did they reach
C. they reach
D. do they reach
解析：考查Only的倒装句。Only放在句子，且强调状语的时候，后面的主句使用部分倒装句。句意：只有他们讨论那个事情几个小时以后，才得出一个决定。