4.2　Identifying topics and points of various levels in the English learning advertisements

Guided by the working principle of global coherence in the previous section，the textual analysis of global coherence in these English learning advertisements in this section will focus on the hierarchical discourse topical network，and how it commands the macro-structure of the genre through verbal texts and pictures.Due to the genre-specific nature of macro-structure，it can be predicted that the English learning advertisements，as a specific mixed genre with features of promotional genre，educational genre and scientific genre，will show unique features in the textual patterns of the construction of global coherence.Furthermore，the multimodal perspective of these advertisements，which means that both verbal elements and pictorial elements will be taken into consideration，determines that the analysis of the hierarchy of discourse topics will be different from the existing studies on schematic structure of purely verbal texts.

First of all，the advertisements in my corpus are analyzed for the identification of recurrent macro-topic，hyper-topics and topics.Secondly，the Points of various levels in the English learning advertisements are analyzed，including macro-point，hyper-points and points.Thirdly，the textual analysis will be performed in a stage-specific manner due to the multi-stage structure of these advertisements identified in Chapter 3.Patterns and features of the verbal and pictorial representation in the main discourse segments will be elaborated in detail in Section 4.3.

Since the topics of various levels are semantic abstractions of what the discourse unit is concerned，they might not be necessarily readily available from the make-up of the concerning discourse unit.