ACT科学实际上考察的是在短时间内定位信息的能力。其中数据分析题考察对图表信息的理解，研究摘要题考察对实验目的，方法和结论的定位，观点冲突题考察对不同假说的区分。

　　本文主要分为两部分：

　　* 研究摘要题中实验目的的提取

　　* 实验部分核心词汇汇总

　　★ 如何在5分钟提取实验目的?

　　实验目的难道不是开篇最后一句话吗?

　　市面上大多数文章都将实验目的简单认定为开篇最后一句话。这种武断的概括往往导致考生在看到最后一句话没有实验目的时感到无所适从，进而迷失在信息的海洋里。

　　我们认为，实验目的的定位有三种可能：

　　1.第一段末句;2.第一段首句;3.如果末句和首句都没有，那么该实验就是研究第一段给出的各变量之间的关系。 下面来看几个例子：

　　1.末句给出实验目的

　　Passage：Some of the liquid in a closed container evaporates, forming a vapor that condenses, reforming the liquid. The pressure of the vapor at equilibrium(when the rates of evaporation and condensation are equal)is the liquid's vapor pressure. A liquid in an open container boils when its vapor pressure equals the eternal pressure. The following experiments were performed to study vapor pressures.(2005年Form 2MC (EEME)) 解析：实验目的由最后一句给出：“to study vapor pressures." 2.首句给出实验目的

　　Passage：Three studies examined the effects of adding fly ash(fine-grained ash from burning coal)to a sandy soil. In the studies, 4 samples were analyzed: Sample 1 was pure sandy soil, Samples 2 and 3 each had a different amount of fly ash thoroughly mixed with sandy soil, and Sample 4 was pure fly ash. (2011年6月Form 67B (HMHM)) 解析：显然实验目的是第一句“examined the effects of adding fly ash (fine-grained ash from burning coal) to a sandy soil." 3.如果末句和首句都没有，那么该实验就是研究第一段给出的各变量之间的关系。

　　Passage：A block is placed on an inclined plane, as shown in Figure 1：

　　The angle of inclination is increased. The angle at which static friction is overcome and the block starts to slide is , the critical angle for sliding. The amount of static friction to be overcome depends on , the coefficient of static friction.(2010年12月Form 62D (EMME))

　　解析：根据我们的思路，如果首句和末句都没有给出实验目的，那么该实验往往是研究第一段中给出的各变量的关系，我们可以看到，第一段引入了变量和，由此，该研究的目的在于研究和的关系。 再来看一个首句和末句都没有给出实验目的的例子：

　　Passage：Eating chips of lead-based paint is a cause of lead poisoning in children. According to the law, paint is considered lead-based if the lead content exceeds 0.5% by weight. Atomic-absorption spectroscopy(AAS) is used to determine the lead content of paint. Samples containing lead in solution are vaporized in a flame, and light of a single wavelength characteristic of lead is shone through the flame. The absorbance measures the amount of light absorbed by the lead in the flame. The following experiments were done using AAS.(2010年12月Form 62D (EMME)) 解析：我们可以看到，首句和末句都没有给出实验目的，根据思路，我们要识别出第一段有哪些变量。

　　我们从“Atomic-absorption spectroscopy(AAS) is used to determine the lead content of paint."以及“The absorbance measures the amount of light absorbed by the lead in the flame,"可以得知，该实验引入了变量lead content和absorbance(这个和light absorbed by the lead in the flame等价)，因此其目的是考察lead content和absorbance之间的某种关系。

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