jumping-off point
noun [ C usually singular ] uk/ˌdʒʌm.pɪŋˈɒf ˌpɔɪnt/ us/ˌdʒʌm.pɪŋˈɑːf ˌpɔɪnt/
起点，出发点
a point from which to start a journey or activity
起点（用于开始某个过程或某项活动的观点、事例或信息）
an idea, example, or piece of information that is used to begin a process or activity
Using his daughter's case as a jumping-off point, he described a justice system that ignores the rights of the victim. 他从他女儿的事情说起，描述了无视受害者权利的司法体系。