This study treats the adverbial clause from the discourse perspective, with focusing on its function as a connector which provides cohesion between successive sentences and paragraphs. Adverbial clause is an efficient device for textual cohesion especially when a new paragraph begins. The intrasentential or intraparagraph linkage by virtue of adverbial clause is generally manifested in two ways, i.e., `tail-head linkage` and `summary-head linkage`. The former is related with that something mentioned in the last sentence of the preceding paragraph is referred by means of back-reference in the following adverbial clause. The latter related with the first sentence of a successive paragraph summarizing the preceding paragraph. This cohesive role of adverbial clause may correspond to the function of `theme` which Maintain cohesion within the discourse to which it is attached. Accordingly, it will be verified that what acts as a discourse conjunction is more close to the preposed clause than the postposed clause, with the former`s common features shared with theme, and this is why the opening of a new paragraph is mostly occupied by adverbial clauses. Besides, adverbial clauses may be used to provide cohesion for an entire discourse by maintaining the discourse perspective and by helping to articulate the sections of discourse. This is realized by means of adverbial clause contributing local background for the whole sentence in which it occurs, and relating previous context with the following one. But the postposed adverbial clause that can not be defined as a typical theme may not function as a connector when it is related only with the main clause. The different behaviors of the pre- and postposed adverbial clauses will be also analyzed from their grammatical manifestations.