Final answer:
Greetings can vary in formality and tone, Representative Communication shows social interactions, and Interjections serve social functions.
Explanation:
Greetings can vary in formality and tone. The greeting 'Good afternoon, Professor McKenna' is the most formal, while 'hi' is informal. The change in tone is influenced by the choice of language and context.
Representative Communication can demonstrate different social interactions. For instance, expressions like 'I'd really like to be able to hang out with my friends sometimes' and 'Don't worry about problems I'm having at work' convey various messages.
Interjections such as 'Hello, Goodbye,' 'Please, Thanks,' or 'Yes, No' serve different social functions, enabling smoother conversations and interactions.
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