A study of social and cultural factors that affect the appropriateness of verbal expressions in different languages focuses on the comparative uses of three common expressions ("thank you, I'm sorry, excuse me" and their equivalents) in English and Chinese. First, the usage patterns of the three expressions are explained briefly, and the study is then described. In the study, a Chinese and English version of a questionnaire were administered to two groups of university students: 19 English-dominant students of Mandarin Chinese at the City College and 26 Mandarin-dominant students of English from English as a Second Language (ESL) classes at Taiwan Normal University. The questionnaires consist of 15 vignettes with questions designed to elicit appropriate verbal behaviors and the reasons for them. Results show that the two subject groups' answers did not correspond on nine of the vignettes, suggesting significant differences in perception of the appropriate behaviors in specific situations. Implications for cross-cultural communication are discussed. (MSE)