(3) He beat three only, ought to be explained, severally, thus:
(1) He did no more than beat, did not kill, three.
(2) He beat no more than three.
(3) He beat three, and that was all he did. (Here only modifies the whole of the sentence and depreciates the action.)
But the best authors sometimes transpose the word. "He only lived" ought to mean "he did not die or make any great sacrifice;" but "He only lived but till he was a man" (Macbeth, v. 8. 40) means "He lived only till he was a man." Compare also, "Who only hath immortality."
Only at the beginning of a statement = but. "I don't like to importune you, only I know you'll forgive me." Before an imperative it diminishes the favour asked: "Only listen to me." This use of only is mostly confined to letters.
Very often, only at the beginning of a sentence is used for alone: "Only ten came," "Only Cæsar approved." Alone is less ambiguous. The ambiguity of only is illustrated by such a sentence as, "Don't hesitate to bring a few friends of yours to shoot on my estate at any time. Only five (fifteen) came yesterday," which might mean, "I don't mind a few; only don't bring so many as fifteen;" or else "Don't hesitate to bring a few more; no more than five came yesterday." In conversation, ambiguity is prevented by emphasis; but in a letter, only thus used might cause unfortunate mistakes. Write "Yesterday only five came," if you mean "no more than five."
*22. When "not only" precedes "but also," see that each is followed by the same part of speech.*
"He not only gave me advice but also help" is wrong. Write "He gave me, not only advice, but also help." On the other hand, "He not only gave me a grammar, but also lent me a dictionary," is right. Take an instance. "He spoke not only forcibly but also tastefully (adverbs), and this too, not only before a small audience, but also in (prepositions) a large public meeting, and his speeches were not only successful, but also (adjective) worthy of success."
*23. "At least," "always," and other adverbial adjuncts, sometimes produce ambiguity.*