There is a classic sentence in another classic written by Charles Dickens. This is the first sentence of A Tale of Two Cities, a very long sentence that has often been cited by many for its beautiful prose and demonstration of parallelism as well as for its timelessness of meaning. In Dickens's novel set against the backdrop of the French Revolution, the author opens his novel with comparisons between his own country of England and France:
IT WAS THE BEST of times, it was the worst of times, it was the age of wisdom, it was the age of foolishness, it was the epoch of belief, it was the epoch of incredulity, it was the season of Light, it was the season of Darkness, it was the spring of hope, it was the winter of despair, we had everything before us, we had nothing before us, we were all going direct to Heaven, we were all going direct the other way—in short, the period was so far like the present period, that some of its noisiest authorities insisted on its being received, for good or for evil, in the superlative degree of comparison only.
Regarding the shortest sentence, the assumption will be made that this sentence cannot be one of dialogue. So, if one does not include any sentences of dialogue, perhaps, then, one of the following can be considered:
This is she.
Twelve gone for ever.
"This is she" is not set in quotation marks; however, it is part of an internal dialogue, so the other sentence, "Twelve gone for ever" may serve as a better example. This sentence comes from Book the Third, Chapter XIII.