the reason why is that是什么从句

the reason why is that是定语从句。定语从句中,关系词选用关系代词(that,which,who等)还是关系副词(when,where,why)取决于先行词在从句中做什么成分。

The reason why…is that…做…的原因是…，其中why引导的是定语从句，that引导的是表语从句，that不可以省略。一个句子中有两个从句，是一个非常好的高级句式。

例如：The reason why he was late for school was that he got up late.他上学迟到的原因是他起床晚了。

注意事项：同学们在使用这个句型时常犯的错误是：1.意识不到why和that后所跟的都是从句，仅凭汉语意识写句子，不会套用句式。2.误把that用成because

例如：The reason why was that he got up late. ×

The reason why he was late for school was that got up late. ×

The reason why he was late was because he got up late. ×