1.Those who would attain the heights reached and kept by great men must keep their faculties polished by constant use, so that they may unlock the doors of knowledge, the gate that guard the entrances to the professions, to science, art, literature, agriculture---every department of human endeavor.

【参考译文】有些人想取得伟人所获得并保持的成就，他们就必须不断运用自身才能，以便开启知识的大门，即那些通往人类努力探求的各个领域的大门，这些领域包括各种职业：科学，艺术，文学，农业等。

【结构解析】“reached and kept by great men”是过去分词做定语，修饰“heights ”，这里的“ faculties”意思是“才能”。

2.If Hugh Miller, after toiling all day in a quarry, had devoted his evenings to rest and recreation, he would never have become a famous geologist.

【参考译文】如果休·米勒在采石场劳作一天后，晚上的时光用来休息消遣的话，他就不会成为名垂青史的地质学家。

【结构解析】这句话的主干是"If Hugh Miller...had devoted..., he would never..."。