used to represent an entire idea, concept, or clause within a sentence that acts as the subject or object of the verb or preposition
如何
used to represent a clause, idea, or concept that acts as the subject or object of the verb or preposition
どれ
used to represent the time when something happens as the subject or object of verb or preposition
いつ
used to represent the place where something took place as the subject or object of verb or preposition
どこ
used to represent a person as the subject or object of verb or preposition in a sentence
誰
used to introduce the reason for an action as the subject or object of the verb or preposition
なぜ
used to represent the manner, method, or means of fulfilling an action as the subject or object of verb or preposition
どうやって
used to represent the person who receives the action of the verb in the relative clause as the subject or object of verb or preposition
だれを
used to represent anything or everything as the subject or object of verb or preposition
何等
used as a placeholder in the sense of any one that or any one of those that
どちらでも