单选题 They had talked only for a few minutes ______ they found they were of different opinions.
【正确答案】 C
【答案解析】[解析] 考查连词。前半句用的是过去完成时had talked，后半句用的是一般过去时found，说明“谈话”是在“发现”之前发生的，故选before。