在做SAT 文法中语法类题目时，当逗号的前面是一个分词结构时，十有八九涉及的考点是逻辑主语一致性，即主句的主语应该和分词结构的逻辑主语保持一致。然而，除了现在分词和过去分词短语之外，还有其他结构也需要保持主语一致的原则。

       统计题库：官方样题、真题、PSAT 和可汗语法

　　考频：平均每一套题都会有一道

　　现根据对考点的归纳总结，将SAT 文法部分逻辑主语一致性的考点作如下分类（五种标志结构）：

　　标志结构一：现在分词／过去分词短语作状语时，主语一致

　　错误句式：Having finished the SAT test, a party was thrown by us.

　　改为：Having finished the SAT test, we threw a party.

　　错误句式：Once appointed supreme commander, stern measures were taken by him.

　　改为：Once appointed supreme commander, he took stern measures.

　　结论：看到标志结构doing/done 作状语, 需考虑doing 的执行者和done 承受者与句子主干部分的主语是否统一，即主干主语=doing 执行者/done 承受者

　　例如Khan 语法‘Toshio Fukuda: Medical Robotics Pioneer’第5 题

　　Working together, innovators in robotics and medicine share their expertise to save lives.

　　A.NO CHANGE

　　B.The expertise of innovators in robotics and medicine is shared to save lives.

　　C.Lives are saved by innovators in robotics and medicine sharing their expertise.

　　D.The sharing of expertise by innovators in robotics and medicine saves lives.

　　做题思路：

　　1. 识别考点：句首有分词状语Working together

　　2. 句子的主语应该和这个状语的逻辑主语（work 的动作执行者）一致。只有A 选项的主语innovators 适合发出work together 这个动作，故选A。

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