本研究旨在從中文口語和書面語料中探討漢語副詞子句的語用功能及其常見的訊息順序結構(preferred information sequence)，特別是將口語語料與書面語中的副詞子句的分佈做一比較。本研究顯示：出現在主要子句前的副詞子句為引述下文之功用，然出現在主要子句後的副詞子句是為補充解釋前面的句子。另一方面，研究結果發現：表時間、條件與讓步子句傾向於出現在主要子句之前，但表原因的子句在一般日常會話中大多出現於主要子句後。此外，絕大部份出現在主要子句後的表原因子句，其所修飾的子句是一結束語調；此表示說話者在說此類子句之前，已經把本來意識焦點中想說的話說完了。換言之，大部份的表原因子句與其主要子句之間的關係極為鬆散，幾乎是獨立存在的子句。這表示在語法上表原因的連接詞其實是個對等連接詞(coordinate conjunction)。一如口語語料，書面語中的表時間、條件與讓步的子句幾乎都出現在主要子句前，作為承上啟下之連繫文段(textual)功能；然表原因的子句出現在主要子句前後約各佔一半。可見表原因的子句之用法與其它類的副詞子句極為不同。此乃口語的特色，即說話者偏好於使用表原因子句來補充說明其前句話，或是回答對方的問題，以消除聽話者的疑惑，具有溝通互動的(interactional)功能。而在書面語中表原因的子句不僅作為承上啟下之連繫文段功能，亦如口語中的表原因子句，可作為補述前句用；此亦可視為作者使用後置的表原因子句作為與讀者產生某種程度互動的手段，正如會話中說話者與聽者的互動一般。

This study investigated adverbial clauses in spoken as well as written Chinese discourse. The adverbial clauses in the spoken data were categorized into (i) initial clauses that occur in the initial position with respect to their linked material across continuing intonation, (ii) final clauses that occur in the final position with respect to their linked material across continuing intonation, and (iii) final clauses that occur in the final position with respect to their linked material across final intonation. Those in the written data were classified into (i) initial and (ii) final clauses that occur in the initial or final position, respectively, with respect to their main clauses. An analysis of the spoken and written data shows that the temporal, conditional, and concessive clauses tend to occur before their linked material/main clause, but that the causal clauses are quite different from the other adverbial clauses. Specifically, the causal clauses commonly appear in the final position with respect to their associated material in the spoken data, while the initial and final causal clauses are nearly evenly distributed in the written data. The data suggest that temporal, conditional, and concessive clauses, like topics, are presupposed parts of their sentences; i.e., all of them may be thought of as establishing frameworks for the interpretation of propositions that follow, which seem to be prototypically textual in their functioning. By contrast, causal clauses in Chinese are noticeably distinct from other adverbial clauses not only in spoken data, but also in written data; they play interactional as well as textual roles in discourse linking.