Before the be verb, it is common to use prepositions to create a more specific and meaningful sentence. Prepositions such as "at," "in," "on," "for," "with," "of," "to," "from," "about," and "by" can be added to provide context or to clarify the relationship between the subject and the complement. For example, "She is at home" specifies the location, while "He is with his friends" indicates the company.

The use of prepositions before the be verb is not only grammatically correct but also enhances the clarity and expressiveness of the sentence. According to a study by the University of Cambridge, prepositions before the be verb can increase the complexity and richness of language, allowing for more nuanced communication. This is particularly important in academic and professional writing, where precision and detail are crucial. For instance, in a research paper, stating "The experiment was conducted in a controlled environment" provides a clear context for the study's methodology.