This paper aims to study the textual function of the double predicate clause with special reference to the basic-level topic and its semantic structure from a cognitive-functional approach. The preliminary research results show that the immediate discourse environment in which the DP clause functions is made up of the prior process that goes before it and the ending process that comes after it. A detailed study is conducted of the prior process, including the resonance it imparts to the DP clause, the linguistic forms it takes and the ways it is related with the DP clause. As the emergent pattern may acquire added value in the context of situation, it follows that the context may imply the prior process for the DP clause. In fact, different kinds of context may cause the emergence of the DP clause. A careful study is also made of the ending process, including what the DP clause expects of it, the linguistic forms it takes and the semantic functions it performs. All this brings to light the full view of the complicated environment in which the DP clause operates. And this is in fact how the DP clause performs its function in various settings in discourse.