THE COMPLEMENTARY INFINITIVE.
28. The infinitive is a form of the verb which expresses merely the general idea of the action or condition indicated, and has some of the characteristics of a noun. The ending of the infinitive is -i, as kuri, to run, esti, to be, havi, to have.
29. An infinitive used to complete the meaning of another verb, serving as a direct object to a transitive verb, is called a complementary infinitive. If the complementary infinitive is from a transitive verb, it may itself have a direct object:
La knabo volas kuri, the boy wishes to run.
Birdoj ŝatas kanti, birds like to sing.
La knabo volas havi ĉevalon, the boy wishes to have a horse.
Ili volas trovi florojn, they wish to find flowers.
INTERROGATION.
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 ĉu. 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:
Ĉu la knabo estas bona? Is the boy good?
Ĉu ili havas florojn? Have they flowers?
Ĉu la kolomboj kantas? Do the doves sing? (Are the doves singing?)
THE CONJUNCTION NEK.
31. In the expression neither ... nor ..., the conjunction nek is used for both words. Since an adjective modifier of two or more words connected by nek must necessarily modify them separately, the adjective remains in the singular number:
Ili nek marŝas nek kuras, they neither walk nor run.
La viro havas nek domon nek ĝardenon, the man has neither a house nor a garden.
Nek la rozo nek la violo estas verda, neither the rose nor the violet is green.