When denoting time, as is an adverb, while is a noun or an adverb, and since is an adverb or a preposition.
- As (or since) you will not listen, I will say no more. [Conjunction.]
- As we crossed the bridge, I looked down at the rushing stream. [Adverb.]
- Ten years have passed since my uncle went to sea. [Adverb.]
- The house has been empty since Christmas. [Preposition.]
369. Conjunctions used in pairs are called correlative conjunctions.
The chief correlatives are:—
- both ... and
- not only ... but also
- either ... or
- neither ... nor
- though ... yet (still)
- although ... yet (still)
- since ... therefore
- if ... then
Examples of correlatives may be seen in the following sentences:—
- Both lions and wolves are carnivorous.
- The culprit looked both angry and ashamed.
- William II is not only German Emperor but also King of Prussia.
- Either brass or copper will do.
- Neither Keats nor Shelley lived to be old.
- He asked me whether I was an Austrian or a Russian.
- Though the roads were very bad, yet he managed to reach Utica before midnight.
- Although he has wronged me, still I cannot believe he is my enemy.
- Since four is the square of two, therefore two is the square root of four.
- If Allen’s testimony is true, then Gilbert’s must be false.
370. But is used as a subordinate conjunction in the sense of but that or unless.
- There is no doubt but that they are murderers.—Shelley.
- Your uncle must not know but [= but that] you are dead.—Shakspere.
- Ne’er may I look on day but [= unless] she tells your highness the truth.—Shakspere. [This use is obsolete.]
- There is not a wave of the Seine but is associated in my mind with the first rise of the sandstones and forest pines of Fontainebleau.—Ruskin.
- There was nobody but loved her.
Note. In the last two examples the subject of the subordinate clause is omitted:—“There is not a wave but [it] is associated,” “There was nobody but [he] loved her.” In such cases, but is sometimes regarded as a relative pronoun.