In a similarly formed sentence the office of the word may be quite different; and, in order to show this fact, the comma is used.
5-1. Now we see we that cannot learn to punctuate until we comprehend the fundamental principles underlying the relations between groups of words, as well as the fundamental principles underlying the use of marks. Now, what are we going to do about it?
In No. 5-1 the first “now” conveys a sufficient idea of time to stand as an adverb, just as “now” does in No. 5; but the second “now” is a mere expletive. To show that it does not sustain its apparent relation, the relation of time, to the remainder of the clause, it is cut off by a comma.
RECAPITULATION
Let us now review and recapitulate the points we have tried to establish in our study thus far:
1. The meaning of language depends very largely upon the groupings of its words. In very simple language, words are so placed that each word is related to a word or words immediately or closely following or preceding it. In such language the reader is hardly conscious that the words are grouped, except into sentences; and no mark may be required, except the end-mark.
2. In more complex language the grouping within the sentence becomes manifest to the reader, and two constructions and two meanings of the language often become possible. In order to notify the reader which meaning the language is intended to convey, the writer may put a sign-board at the point where the meaning may be mistaken. The reader reads the sign-board, and thus keeps on the right line of thought-development.
3. In the sentences thus far studied, except No. 3-1, marks were used simply to aid the reader to catch the meaning quickly by avoiding a wrong grouping of words. In No. 3-1 the meaning of the language was entirely changed by the marks.
[Examples will be found at the end of Chapter II]