Lesson Seven (Leciono Sep): Circumstances and Questions
The rhetorician, Hermagoras of Temnos, is attributed as inventing the "elements of circumstance" which is the foundation of the "Five Ws" in basic journalism. Esperanto asks these questions with "K" words and, as an example of correlation which often appears in the language, answers them with "T" words.
Esperanto English Kiu? Who?/Which [person]? Kio? What? Kiam? When? Kie? Where? Kial? Why? Kiel? How? Kiom? How many?
Esperanto English Tiu That/That person Tio That [thing] Tiam Then Tie There Tial That [reason] Tiel Thus Tiom That [many]
To change a standard sentence into a question, simply place the word "cxu" in front of it. So the phrase gxi estas hundo ("it is a dog") can be changed into a question Cxu gxi estas hundo? ("Is it a dog?").