When we want to convey an idea or thought, we often use different words to express it. Synonyms are words that have similar meanings, and they help us to avoid repetition and make our language more varied and interesting. The phrase "are expressed by" can be replaced with various synonyms, including "are articulated by," "are communicated through," "are conveyed by," and "are stated by." Depending on the context, these alternatives can bring a different tone or emphasis to a sentence. By using a broad range of synonyms, we can improve our writing style, enhance clarity, and engage our audience.