In conversation, adverbial clause subordination is most commonly achieved through temporal, conditional, concessive, and causal conjunctions, such as dang (``when``), rnguo(``if), suiran (``although``), yinwei (``because``), etc. in Mandarin Chinese. This study aims at exploring adverbial clauses in spoken Mandarin conversations on the basis of quantitative analysis. There were two-hour conversation database in this research. The adverbial clauses in our database were divided into (a) preposed clauses to their modified material with continuing intonation, (b) postposed clauses to their modified material \-vith continuing intonation, and (c) postposed clauses to their modified material with final intonation (rising question intonation or final falling intonation) After an inspection of our data, we fmd that the temporal, conditional, and concessive clauses favor to occur before their modified material; and the causal ones, after their associated material. Our data show that causal clauses are fundamentally different from temporal, conditional, and concessive ones in their use.