学好从句之前学好句子的成分很重要。
Before the bullet train service existed,(时间状语)passengers (主语)traveling from Baigou or Baiyangdian to Beijing, (定语)had to transfer(谓语) in Baoding or Tianjin,(地点状语) which cost 82 yuan or 97 yuan respectively.(非限制性定语从句)
在高速列车服务(高铁)出现之前,从白沟或白洋淀到北京的乘客,
必须在保定或天津转车,需要分别花费82元和97元。
Before the bullet train service existed ,passengers traveling from Baigou or Baiyangdian to Beijing,
had to transfer in Baoding or Tianjin, which cost 82 yuan or 97 yuan respectively.
istalkingto是现在进行时,充当谓语,yourmother是宾语。