Today "why" is used as a question word to ask the reason or purpose of something. I don't know why, but it seems to me that bob would sound a bit strange if he said, "why is it that you have to get going?" in that situation. You never know, which is why.
Only have similar answers where the reason for something is the cause. Aug 22, 2025the history told me nothing why an involuntary, extremely painful spasm, is named after a horse called charley. What part of speech is "why?" i think it modifies the verb "is", so i think it is an adverb.