【正确答案】 1、he had betrayed us    

【答案解析】[考点] 动词时态。句子中有序数词(first/second/third...)时后面定语从句用完成时态。
[拓展] it is the first time that...句型中，that从句用完成时；It is high time that...句型中，that从句用虚拟语气(did或should do)。注意区分。