从句是英语语法中的一个重要概念，它由一个主句和一个或多个从句组成，从句在主句中充当一定的成分，如主语、宾语、表语、定语或状语等。下面是一些从句的例句及其句子成分分析：
名词性从句
例句：What he said is true.
主语从句：What he said
谓语：is
表语：true
定语从句
例句：The book that I borrowed from the library is very interesting.
定语从句：that I borrowed from the library
主语：The book
谓语：is
表语：very interesting
表语从句
例句：The reason why he didn't attend the meeting remains a mystery.
表语从句：why he didn't attend the meeting
主语：The reason
系动词：remains
表语：a mystery
宾语从句
例句：I wonder when she will arrive.
宾语从句：when she will arrive
谓语：wonder
宾语：when she will arrive
状语从句
例句：She will call me when she arrives.
状语从句：when she arrives
主句谓语：will call
时间状语从句：when she arrives
从句的成分分析包括识别从句中的主语、谓语、宾语等成分，并理解它们在句子中的作用。希望这些例句和分析能帮助你更好地理解从句的用法和结构。