发布时间:2025/12/09 17:39:37
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今天来讲一个SAT红词:proxy!在澜大教育的SAT阅读课堂中,我们常常会带着同学们拆解那些看似冷门却极具代表性的真题词汇。今天要讲的“proxy”不仅是SAT红词,更是科学研究和逻辑推理题中反复出现的核心概念。借助一道曾出现在2023年机考中的经典旧题,我们将带你从阅读理解、科学逻辑到选项推理,全方位掌握这个词在考试中的真正考点。

Some fuel additives contain cerium oxide nanoparticles (CeO2 -NPs), which can leach into waterways and soils via wastewater. In a 2015 study, Mael Garaud and colleagues found that CeO2 -NPs can accumulate in the bodies of zebra mussels (Dreissena polymorpha). While bioaccumulation of manufactured nanoparticles may be inherently worrisome, it has been hypothesized that CeO2 -NPs bioaccumulation in invertebrate like D. polymorpha could serve a valuable proxy role, obviating the need for manufacturers to conduct costly and intrusive sampling of vertebrate species— such as rainbow trout (Oncorhynchus mykiss), commonly used in regulatory compliance testing—for manipulative bioaccumulation, as environmental protection laws currently require.
Which finding, if true, would most directly weaken the hypothesis presented in the text?
A. When D. polymorpha and O. mykiss are exposed to similar levels of CeO2 -NPs, concentrations of CeO2 -NPs in animals of both species show little variation from individual to individual.
B. The rate of CeO2 -NP uptake in D. polymorpha differs from the rate of CeO2 -NP uptake in O. mykiss in a way that is not yet well understood by researchers.
C. D. polymorpha has been shown to accumulate several other types of manufactured nanoparticles in addition to CeO2 -NPs, whereas O. mykiss has been shown to accumulate only CeO2 -NPs.
D. Compared with O. mykiss, D. polymorpha can accumulate detectable CeO2 -NP concentrations with significantly fewer negative effects.
今天选取的这道题可是SAT老题了,23年机考伊始就出现过。
这道题的关键点有两个:
1, Regulatory compliance testing 即合规检测
首先我们要搞清楚对 CeO2 -NP 进行 bioaccumulation的目的是什么,文章最后一句说的很清楚,环保部门要求的,拿生物进行合规检测(一般是脊椎动物,因为在食物链上离人最近)。
2, Proxy role 替代品
这个词可以说是全文的中心。我们先来看一下字典里对proxy的解释:the agency, function, or office of a deputy who acts as a substitute for another。所以全文的假设可以被我们替换成:用无脊椎动物D. polymorpha 来代替脊椎动物O. mykiss进行合规检测(thus avoiding the intrusive nature and cost of vertebrate sampling)。
文章理解到这一步已经初见曙光了,但很多学生还是会出错,因为他们不知道“代替”在这里意味着什么?
这就要从科学研究的角度去理解了。科学研究中有一个词叫替代变量,即proxy variable
有些时候,我们无法对感兴趣的变量进行直接测试,就会选取一个替代变量,即proxy variable, 用来进行间接测试,这就要求替代变量与原变量间必须有强相关性。
应用到这道题就是:无脊椎动物D. polymorpha与脊椎动物 O. mykiss在生物吸收方面是强相关(correlate strongly)的,即无脊椎动物D. Polymorpha对 CeO2 -NP的吸收情况可以可靠地预测(consistently predict)脊椎动物 O. mykiss对CeO2 -NP的吸收情况。
那么答案就出来了,选B:D. polymorpha与O. mykiss 对 CeO2 -NP的吸收率不一样,原因不明。
吸收率不一样就不能可靠地预测,文章假设不成立。
SAT阅读从来不是单纯背词或套公式,真正的提升来自于对逻辑结构与科学思维方式的深度理解。澜大教育也会持续为同学们精选SAT红词与经典真题,通过拆解文章逻辑、构建知识体系,帮助你在理想的时间内建立可迁移的高分思维。希望今天的“proxy”讲解能让你在遇到科学类文章时更有策略、更有信心。
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沪公网安备31010102007782





