1. Although these molecules allow radiation at visible wavelengths, where most of the energy of sunlight is concentrated,to pass through,they absorb some of the longer-wavelength,infrared emissions radiated from the Earth's surface,radiation that would　otherwise be transmitted back into space. (4)

　　虽然这些分子允许可见波长(visible wavelength)的辐射——阳光的绝大部分能量就汇集于此——不受阻挡地穿透，但它们却会吸收某些较长波长(longer-wavelength)，亦即从地球表面辐射出的红外发射(infrared emission)，这种辐射若不是二氧化碳的缘故就会被重新输送回太空。

　　难句类型：复杂修饰、抽象词

　　解释：前面的分句中有一个不算很长的插入语，但是因为它插入的位置正好在固定搭配allow something to do somthing中间，将allow和to分得很远，所以读起来让人感觉很不舒服。

　　后面的分句中的最后一行radiation that would otherwise be transmitted back into space是其前面的infrared emissions的同位语。其中的otherwise是副词作状语，表示如果后面的分句所说的they absorb some of the longer-waverlength, infrared emissions不发生时的后果。

　　意群训练：Although these molecules allow radiation at visible wavelengths, where most of the energy of sunlight is concentrated, to pass through, they absorb some of the longer-wavelength， infrared emissions radiated from the Earth's surface,radiation that would　otherwise be transmitted back into space.

　　2. The role those anthropologists ascribe to evolution is not of dictating　the details of human behavior but one　of imposing constraints—ways of　feeling,thinking,and acting that　"come naturally" in archetypal situations in any culture. (4)

　　这些人类学家所归诸于生物进化的作用，不是规定人类行为的种种细节，而是将各种限制强加于人类——即在任何文化的典型情景中都会“自然表露”的情感、思维、以及行动方式。

　　难句类型：复杂修饰、省略

　　解释：尽管我们很熟悉the role of something的这种表达，但本句中the role of被作者胜利很活。首先，在role后面有一个省略了引导词that的定语从句(因为role在从句中作ascribe的宾语)，这样就把role和系动词is隔得很远。其次，but前面的句子的主要结构The role is not of doing something其实是The role is not the role of doing something的省略形式，因为后面的the role与前面的完全重复，如果不把它省略掉，谁看到都要觉得啰嗦。因为同样的道理，but之后的one of imposing constraints实际上是is one role of imposing constraints的省略形式。

　　意群训练：The role those anthropologists ascribe to evolution is not of dictating　 the details of human behavior but one　of imposing constraints— ways of　feeling, thinking,and acting that　"come naturally" in archetypal situations in any culture.

　　在GRE阅读中需要明白GRE阅读长难句才能理解整篇文章的意思，因此需要各位考生认真备考。只要你合理地安排时间，科学的掌握背诵技巧。平时多积累，短时间内，相信你的GRE阅读长难句肯定会有所突破！