某列车通过250米长的隧道用25秒，通过210米长的隧道用23秒．问：该列车与另一列长320米、速度为64.8千米/时的列车错车而过需要几秒？
We find _______ necessary to give children time and freedom to relax.
Gian Tara is studying Chinese history and culture now. They find them rich and amazing.
，则
与
的关系为 （ ）