How about the shortest sentence? A complete sentence in English requires a subject (noun or pronoun) and a predicate (at least a verb). But because imperative (command) sentences can imply the subject "you," one has only to find the shortest verb. Thus, the shortest sentence has a small handful of equal possibilities in a single two-letter verb such as "Go!" In a pinch, "Do" and "Be" could work, but they sound awkward without something else in the predicate. Without using a Scrabble word list, can you think of others?