Final answer:
A sentence illustrating an appropriate tone and vocabulary for a letter of complaint should be polite, respectful, and factually clear without resorting to humor or overly emotional language.
Step-by-step explanation:
When crafting a letter of complaint, your tone should be polite and courteous, and the language choices should suit the audience and purpose. To illustrate an appropriate tone and vocabulary for such a letter, consider this sentence: 'I am writing to express my concern regarding the service I received at your establishment on [date]. Despite my repeated attempts to address the issue with your on-site team, unfortunately, the matter remains unresolved, which prompts me to seek assistance through this communication.'
This example maintains a respectful tone, provides clear information, and avoids overly casual language or humor that can be misinterpreted. It reflects careful thought, fairness, and comprehension of the rhetorical situation. In contrast, using overly emotional language, making unfounded accusations, or resorting to sarcasm would be inappropriate and could undermine the effectiveness of the complaint.