Tip: The formality or informality of diction or language is not absolute,but relative.Much writing you do everyday is neither exclusively formal nor completely informal.However,you should be aware of and be sensitive to the different levels of formality,choose words that are appropriate to your rhetorical context(subject,audience,and purpose),and try to maintain a consistent level of formality. g An essay written with a mixture of formal,informal. colloquial,and slang expressions would taste like a drink mixed with expensive French wine and cheap locally brewed(酿造)beer.Tip: v The formality or informality of diction or language is not absolute, but relative. Much writing you do everyday is neither exclusively formal nor completely informal. However, you should be aware of and be sensitive to the different levels of formality, choose words that are appropriate to your rhetorical context (subject, audience, and purpose), and try to maintain a consistent level of formality. v An essay written with a mixture of formal, informal, colloquial, and slang expressions would taste like a drink mixed with expensive French wine and cheap locally brewed(酿造) beer