PHRASE ADVERBS
287. We have certain little phrases which we have used so often that they have come to be used and regarded as single adverbs. They are such phrases as of course, of late, for good, of old, at all, at length, by and by, over and over, again and again, through and through, hand in hand, ere long, in vain, to and fro, up and down, as usual, by far, at last, at least, in general, in short, etc. These words which we find used so often in these phrases we may count as single adverbs.