宾语从句当然有引导词,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 don't 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....