The poetry of mere day and of late summer becomes perceptible to mature eyes that have long ceased to be sated, have taken leave of weariness, and cannot now find anything in nature too familiar

解答：that have long ceased to be sated, have taken leave of weariness, and cannot now find anything in nature too familiar为定语从句修饰前面名词“mature eyes” ,关系代词that代替前面先行词“mature eyes”并在定语从句作主语，cease, have taken , can't find为定语从句3个并列谓语动词，find anything too familiar为动词find+不定代词+形容词 结构。

备注：can’t now find anything in nature too familiar=can’t now find anything too familiar in nature.现在在自然界中不能找到任何太熟悉的东西。

The poetry of mere day and of late summer【主语】// becomes【系动词】// perceptive 【表语】//to mature eyes【状语】// that have long ceased to be sated,have taken leave of weariness,and cannot now find anything in nature too familiar【that 引导限制性定语从句】