In compound sentences, the semantic structure has two separate components: representational meaning (the state of affairs described) and modality (feeling, attitude, evaluation towards things mentioned). These two components are always in a close and interactive relationship to form the structure of meaning in the sentence. Based on the study of the relationship between states of affairs which form the compound sentences, this paper focuses on the structure of representational meaning in terms of the similarities and differences between states of affairs and the relationship between the arguments (having the same or different fundamental and extended participants).