填空题 If only she (know) that her behavior was not welcome, she would have been more careful with it.

  • 1、
【正确答案】 1、had known    
【答案解析】[考点] 虚拟语气
[解析] 此处空格所在的从句为虚拟语气的条件从句，表示与过去事实相反的假设，所以应该用其过去完成时。