30. An interrogative sentence is one which asks a question. Unless some
directly interrogative word (as "who," "when," "why," etc.) is used,
the sentence is rendered interrogative by use of the word "cxu". This
interrogative particle is placed at the beginning of a sentence, the
words of which are left in the same order as for a statement. Since
there is no inversion of order, there is no necessity for a word like
English "do" or "does," to introduce the verb:
Cxu la knabo estas bona? Is the boy good?
Cxu ili havas florojn? Have they flowers?
Cxu la kolomboj kantas? Do the doves sing? (Are the doves singing?)