Interrogative adverbs in Vietnamese grammar play crucial roles in constructing questions. Vietnamese, like any other language, uses interrogative adverbs to inquire about particular details such as time, place, reason, manner and quantity. The common Vietnamese interrogative adverbs include: Sao (Why), Bao nhiêu (How many), Bao giờ (When), Đâu (Where), Như thế nào (How) etc. The placement of these interrogative adverbs can affect the meaning and context of the question.