Bonjour David, Qu'est-ce que and que are pretty much synonymous ---> what. Qu'est-ce qui, when using this phrase, it will ALWAYS be followed by a verb whereas qu'est-ce que will be followed USUALLY by a noun or other subject in the same manner as que tu est triste instead qui est triste. Here are a couple of links that might help: https://www.thoughtco.com/qui-vs-que-1368925 (this one is written by Laura from this site) https://www.laits.utexas.edu/tex/gr/int5.html Hopefully these additional resources can help clarify this for you. Bonne chance et bonne continuation !

You use "Qu'est-ce qui..." if "qui" is the subject of the following sentence. And you use "qu'est-ce que..." if "que" is the direct object of the sentence. For example: Qu'est-ce que tu as fait? -- What is it that you did? (literal translation) Here "you" is the subject of the clause and "que" (=that) is the direct object. Hence: que. Qu'est-ce qui fait le bruit? -- What is it that makes this noise? "Qui" is the subject of the clause (... THAT makes the noise), hence "qui" and not "que". Did that help any? -- Chris (not a native speaker).

Bonsoir, While I fully understand the response given by Chris, I still have a relevant question. After re-reading this question that was posed, I have the sense that possibly we both missed the intent of the question. My take-away is this: In what scenario would one choose to use «qu'est-ce qui» instead of just «que» and vice versa. Also in the same manner when would one use «qui est-ce qui» instead of just «qui»? Most things concerning the French language have definite guidelines when one form is preferred over another, is there a similar guideline for these examples? I have re-read the lesson and cannot find a discernible explanation. Merci en avance, Ron