355. The following words and expressions are grammatically independent of the rest of the sentence; that is, they are not a necessary part, do not enter into its structure:—
(1) Person or thing addressed: "But you know them, Bishop;" "Ye crags and peaks, I'm with you once again."
(2) Exclamatory expressions: "But the lady—! Oh, heavens! will that spectacle ever depart from my dreams?"
Caution.
The exclamatory expression, however, may be the person or thing addressed, same as (1), above: thus, "Ah, young sir! what are you about?" Or it may be an imperative, forming a sentence: "Oh, hurry, hurry, my brave young man!"
(3) Infinitive phrase thrown in loosely: "To make a long story short, the company broke up;" "Truth to say, he was a conscientious man."
(4) Prepositional phrase not modifying: "Within the railing sat, to the best of my remembrance, six quill-driving gentlemen;" "At all events, the great man of the prophecy had not yet appeared."
(5) Participial phrase: "But, generally speaking, he closed his literary toils at dinner;" "Considering the burnish of her French tastes, her noticing even this is creditable."
(6) Single words: as, "Oh, yes! everybody knew them;" "No, let him perish;" "Well, he somehow lived along;" "Why, grandma, how you're winking!" "Now, this story runs thus."
Another caution.