It is assumed that all the three levels of coherence construction in the multimodal discourse have influence on the readers'appreciation of it.When all the three are strongly or well constructed，the multimodal discourse will be a well-organized one and highly appreciated by readers.In other words，for a multimodal discourse to receive a high evaluation，it must satisfy the following conditions at the same time：

（1）The signs in it，both verbal and pictorial，should fit well into the discourse topic，or at least，into the key topics in the main stages in the discourse.

（2）The signs of different semiotic systems should have close semantic connections with each other inside the stages and phases.

（3）The structure in the layout should be clear and orderly.The typographical features，such as the use of color and size，and spatial arrangement should be balanced and harmonious.

The first condition corresponds to the global coherence—relevance with the discourse topic，the second to local coherence—the semantic connection between adjacent elements，the third to the layout structure and salience of the discourse which are aspects of the surface cohesion.