托福阅读长难句精讲： that引导主语从句

## 托福阅读长难句 For decades, scientists wondered how the offspring of an alga and a fungus got together to form a new lichen; it seemed unlikely that they would just happen to encounter one another. ### 【子句拆分】 并列句1： For decades, scientists wondered sth. 宾语从句：The offspring of an alga and a fungus got together to form a new lichen. 并列句2：It seemed unlikely. 主语从句：They would just happen to encounter one another. ### 【成分划分】 并列句1： For decades [状语], scientists [主语] wondered [谓语]. 翻译：数十年来，科学家想知道。 连接词： how 宾语从句：The offspring of an alga and a fungus [主语] got together [谓语] to form a new lichen [状语]. 翻译：藻类和真菌的后代聚集在一起形成一个新的地衣。 并列句2： It [主语] seemed [系动词] unlikely [表语]. 翻译：这看起来不可能。 连接词：that 主语从句：They [主语] would just happen to encounter [谓语] one another [宾语]. 翻译：它们只是碰巧遇到彼此。 ### 【全句翻译】 数十年来，科学家想知道藻类和真菌的后代是如何聚集在一起形成一个新的地衣；它们不可能只是碰巧遇到彼此。 ## 知识点梳理 ### that引导主语从句 一. that可以用来引导主语从句，that引导的主语从句如果不是很长的话，可以放在句首。 That she is a single lady astonishes many people. 二. that引导的主语从句如果很长的话，可以放在句末，用 it 作形式主语。 常见的 it 作形式主语，that 引导的主语从句放在句末的常见句型有： 1. it+be+过去分词+that从句 2. it+be+形容词+that从句 3. it+be+名词短语+that从句 4. it+不及物动词+that从句 上面这句话里面的结构就是：it seems that，就是 it 作形式主语，seem 作表语，that引导的主语从句才是真正的主语。