英语句子语法的问题
for example,one graphic illustration to which children might readily relate is the estimate that rianforest are being destroyrd at a rate equiralent to one thousand football fields every forty minutes-about the duration of a normal classroom period.这个句子中to which children might readily relate 中的which前面的to是什么意思,为什么会有个to?从语法上怎么解释?求帮帮手.