文档介绍：Punctuation
The comma (,)
★ A comma is used to join coordinate clauses. It is put before the conjunction (and, but, or, for, so, nor or yet)
He wanted to go on, but other people disagreed.
Nobody was listening, for everybody was shouting to be heard.
★ A comma is used after an adverbial clauses or phrase, including a prepositional and a participial phrase placed before the subject, or inserted in the middle of the sentence.
On hearing about the accident, he went to the site at once.
Some listeners, bored by the lengthy talk, closed their eyes and dozed off.
★ Commas are used to separate a series of words or phrases with the same function in the sentence.
The children sang, danced, jumped and chased each other.
Present at the party were Dean Lee, Professor Brown, Associate Professor Major, and a few other members of the faculty.
★ Nonrestrictive clauses and phrases are set off by commas.
The speaker, after glancing at his notes, began to talk about the next point.
★ Commas set off parenthetical elements.
The machines you have supplied us, I am glad to tell you, work very well.
★In dates, a comma is used to separate the day and the year if the order is month—day—year
July 1, 1997
★With the numbers of 1 000 or over, commas or little blank spaces may be used to separate digits by thousands.
1, 234, 300
The period (.)
★ The period is used at the end of a declarative sentence, a mildly imperative sentence and an indirect question.
Punctuation marks are important in writing.
Don’t overuse punctuation marks.
She asked the teacher how parentheses are different from brackets.
★ The period is used with most abbreviations.
Mr. Feb. . . Mon.
The semicolon (;)
★ The semicolon is used between two coordinate clauses which are not linked by a conjunction.
She does not like the film; she is disgusted with it.
★ Conjunctive adverbs like therefore, however, nonetheless, hence, besides, moreove