What is the you are working on so I can suggest the best replacement?
: (Formal) "Refer to the aforementioned document." As a Relative Pronoun (Connecting ideas) Which : Used for non-essential info. " That which is mine..." →right arrow "The car, which is red..." synonyms-of-that
: Not all synonyms are interchangeable. For example, "perfect" and "flawless" are total synonyms, but many others depend on the surrounding words to make sense. What is the you are working on so