宾语从句引导词,一般是三种：

1、如果宾语从句不缺少任何成分,则引导词为that,不过that有时经常可以省略。

如：I dont know (that) he is a teacher.

2、如果宾语从句缺少“是否”的疑问词,则引导词为if/whether.不过用whether最好,有时候if是不能使用的。

如：I want to know if/whether you are good at English.

3、如果宾语从句缺少其他成分,则引导词为相应的可以补充句子完整的疑问词,一般分为疑问代词who/whom/what/which/whose或疑问副词when/where/why/how等。

如：Can you tell me how I can get to the bus station?

I dont know who you are looking for.