“Are you going to Australia?” is an interrogative sentence in English. It is a Yes/No question because it expects an answer such as “Yes, I am” or “No, I am not.” From the point of view of the structure of English, this sentence is an example of an interrogative construction formed through subject–auxiliary inversion. The sentence consists of the auxiliary verb “are,” the subject “you,” the verb phrase “going,” and the prepositional phrase “to Australia.” In a declarative sentence, the normal word order would be “You are going to Australia.” Here, the auxiliary verb “are” comes before the subject “you,” producing the interrogative form “Are you going to Australia?” This change in word order is one of the important structural features of English questions. The word “are” is a form of the verb “be.” In this sentence, it functions as an auxiliary verb rather than as the main lexical verb. It combines with the present participle “going” to form the present progressive construction “are going.”