impenetrable: 难以渗透的; incapable of being penetrated or pierced
pierce : impenetrable = change : immutable 穿透:难以渗透的=改变:不可改变的
pierce : impenetrable = profane : inviolable
pierce : impenetrable = understand : recondite
【考法1】adj. 不可渗透的，不可穿透的： impossible to get through or into
【例】 The ancient temple was surrounded by vast stretches of impenetrable jungle. 包围着古老的神庙的是密不透风的灌木丛
【近】 impassable, impermeable, impervious, impregnable
【反】 passable, penetrable, permeable, pervious 可通过的
【考法2】adj. 难以理解的： incapable of being comprehended
【例】The textbook's language is completely impenetrable, at least to me. 至少在我看来，这个教材就是天书
【近】 arcane, cryptic, enigmatic, incomprehensible, inscrutable, unfathomable, ungraspable, unintelligible
【反】 fathomable, intelligible, understandable 可以理解的
