As you know, using the same phrase repeatedly can make your writing sound monotonous and uninteresting. Fortunately, there are several great alternatives to the commonly-used phrase "as you know". For instance, you can write "as you're aware" or "as you might recall" to convey the same meaning. Another great substitute is "it's no secret that" or "it's well-known that". Additionally, you can try "as we've discussed before" or "as I've mentioned previously". Using synonyms for "as you know" can add variety to your writing and emphasize your message in a more engaging way.