首先你得明确先行词这个概念.
什么叫做先行词?
例,he is a hard-working student.
句子成分分别为主语,谓语,定语,表语.
变为定语从句后,he is a student who is hard-working.
who 为引导词,引导定语从句修饰student.
student 为先行词,也就是被修饰的词.
因此,其他从句是没有先行词的,除了定语从句和同位语从句.
给个同位语从句的例子,the news that he won the match made us surprised.
the news 是先行词,that 为引导词.
再强调一下,其他从句是没有先行词的,除了定语从句和同位语从句.