MOCK TEST 1 There are four locations [■] in the passage that indicate where the following sentence could be added. Where would the sentence best fit? Select a location [■] to add the sentence to the passage.

1. 题干：There are four locations in the passage that indicate where the following sentence could be added. Where would the sentence best fit? 文章中有四个位置标记表示可以添加以下句子。这个句子最适合添加在哪里？ 2. 分析：句子插入题。解答此题需要分析待插入句子的内容与逻辑功能，并判断其与原文中每个可能位置前后文的逻辑衔接、指代关系和话题连贯性。 3. 定位信息理解：待插入句子为：“Its properties challenge our commonsense notions about matter.” 该句为概括性陈述，指出暗物质的“性质”挑战了我们对物质的常识认知。代词“Its”指代前文必须明确出现的“暗物质”，且其内容应能自然衔接前后文。 4. 分析选项：位置2 (在“Advanced experiments...”之前)： 前文为“Scientists have proposed candidates... but none have been conclusively detected.” 插入句在此能最直接地解释“为何难以探测到”——正是因为其性质违背常识，导致常规方法失效。同时，“properties”一词能完美引出下文“旨在理解它们的性质”的实验目标。此为正确答案。