Avenir is a defective verb.
																			This verb only exists in infinitive, in present participle and present gerondive.
																											Here are several examples of defectives verbs: 
bruire, 
distraire, 
traire, 
extraire, 
soustraire, 
paître.
																																																																																									
Avenir is conjugated in interro-negative form. The interro-negative form being obtained by inversion of the subject, the placement of the negative adverb follow the same rules as in negative form, giving the following rules:
									
 - in interro-negative form, the adverb 
« ne » is always placed first if the subject is a pronoun.
									
 - in simple tenses, the adverbs (
« ne ...pas », 
« ne...plus », 
« ne...jamais », etc...) surround the verb 
avenir and the inverted subject pronoun.
									
 - in compound tenses or in passive voice, the negative adverbs surround the auxiliary and the inverted subject pronoun.
																		
																											
Finally, the interrogative form does not exist in subjunctive and imperative.