The present study delves into the idiosyncrasies of three Chinese synonyms – yexu, keneng, and haoxiang, by adopting a corpus-based approach to analyze their similarities and differences. The treatment of yexu, keneng, and haoxiang in modern Chinese synonym dictionaries and published studies is reviewed, synthesized, and discussed in terms of part of speech, meaning, placement in sentences, and sentence patterns. Then drawing upon the Academia Sinica Balanced Corpus of Modern Chinese as a data source, the frequency of occurrence and use of the three targeted stance adverbs was investigated. The data reveals that all three stance adverbs are used to express uncertainty when they occur before subjects and function as a cohesive device when appearing at the beginning of sentences. Furthermore, it was found that the functions of three stance adverbs depends on the sentence pattern in which they appear. Other findings were that yexu occurs more frequently in rhetorical sentence patterns, keneng takes on many more parts of speech and occurs in more varied sentence patterns, and haoxiang is used to express the strongest tone and is prevalent in sentences containing similes. These and other similarities and differences found are further discussed.