ittakesmeabout20minuterstowalktoschool
=Ispendabout20minuterswalkingtoschool.
花费时间做某事的用法.
ittakestimetodosth
sbwastetimedongsth.
towalktoschool中前面的是ittakestimetodosth搭配的用法,后面的to的是介词.
如果改为回家则是:ittakesmeabout20minuterstogohome.就没有第二个to,home是地点副词其前面不能加介词to.