2010年考研英语一真题句子解析： It is difficult to the point of impossibility for the average reader under the age of forty to imagine a time when high-quality arts criticism could be found in most big-city newspapers.

It is difficult to the point of impossibility for the average reader under the age of forty to imagine

形式主语 "It" 与真正主语不定式 "to imagine..." 之间被插入了多个成分：形容词 "difficult"、程度状语 "to the point of impossibility"、以及不定式的逻辑主语 "for the average reader under the age of forty"。这些成分使得读者需要跨越较长距离才能找到句子的真正主语，造成主干识别的困难。

It is difficult to the point of impossibility for the average reader under the age of forty to imagine a time when high-quality arts criticism could be found in most big-city newspapers.

句首的 "It" 不指代任何实体，仅占据主语位置。真正的主语是后置的不定式短语 "to imagine a time when high-quality arts criticism could be found in most big-city newspapers"。这是形式主语的标准结构：It + be + 形容词 + (for sb.) + to do，其中 "for the average reader under the age of forty" 指明不定式的逻辑主语。

to imagine a time when high-quality arts criticism could be found in most big-city newspapers

不定式短语 "to imagine..." 作为真正主语包含一个宾语 "a time"，该宾语后跟定语从句 "when high-quality arts criticism could be found in most big-city newspapers" 进行修饰。结构为：主句层 → 不定式层（第一层嵌套）→ 定语从句层（第二层嵌套）。这构成了两层嵌套结构。

It is difficultto imagine a time when high-quality arts criticism could be found in most big-city newspapers

本句是 "it is + 形容词 + to do" 结构的典型应用，但在形容词 "difficult" 后插入了程度状语 "to the point of impossibility"，在不定式 "to imagine" 前插入了 "for the average reader under the age of forty" 表明逻辑主语。

识别要点：首先确认 "It" 是形式主语（不指代任何具体事物），"is difficult" 是系表结构，真正的主语是后置的不定式短语 "to imagine a time..."。去掉 "It is difficult" 后，句子缺少主语，这证明这是形式主语结构而非强调句。

插入成分的处理："to the point of impossibility" 是程度状语，修饰 "difficult" 的程度，不改变句型结构。"for the average reader under the age of forty" 说明不定式动作的逻辑主语是谁。这些插入成分增加了句子复杂度，但不改变核心句型。

翻译逻辑：先识别真正主语（不定式短语表达的动作），再结合形容词理解评价，最后补充逻辑主语。本句译为："对于40岁以下的普通读者来说，要想象一个能在大多数大城市报纸上找到高质量艺术评论的时代是困难的（几乎不可能）"。

可迁移方法：遇到 "It is + 形容词" 开头的句子，先判断 "It" 是否有实指，若无则向后寻找 "to do" 或 "that从句" 作为真正主语。若中间有插入成分（如程度状语、逻辑主语标记），先跳过识别核心结构，再回头处理修饰成分。