In this article, búshì in Mandarin Chinese is divided into Type 1 default use, that is, the negation bú shì, and the Type 2 marked use, that is, the confirmation búshì. These two different uses of búshì are different in their semantic meaning and pragmatic functions no matter whether they take the form of or are embedded in declarative or interrogative grammatical constructions. It is demonstrated that Type 2 búshì in declaratives is in fact a practice that enables its speaker to fulfil the task of premonitoring or telling an everyday trouble or problem, and, furthermore, analysis is done to find out how the co-participants respond, hence working together with trouble tellers to form a specific sequence organisation of everyday trouble alluding or reporting in Mandarin Chinese. Specifically, the troubles talk signalled or reported by búshì falls into two kinds. In one kind, búshì-containing turn construction units (TCUs) only alert or signal to recipients that a trouble may be forthcoming. In the other kind, the búshì-containing TCUs are themselves explicit reportings or tellings about a trouble. These two kinds of búshì-containing TCUs lead to different sequence organizations: the former develops into a full elaboration of the volunteered troubles, and the latter continues with solutions to the troubles. The present study contributes to understanding Mandarin grammar from a functional perspective.