Question words: Introduction. We also call them interrogative words, WH question words, wh-words, interrogative pronouns. Why important? Because most of our speech consists of questions and statements. I highly recommend to study this topic. Below you will find links to all question words in modern English.
- Who: subject/object question, whom
- Which: Which of / who of
- How: How old/fast/long/many/much
- Why vs what for?
- For what reason vs for what purpose
One of the sources: