자료 1. When to Use a Comma before "And"
Two specific situations call for the use of a comma before "and."
- The first is created when we have three or more items in a series. This mark of punctuation is called the serial comma. ....
- The second situation occurs when "and" is being used to coordinate two independent clauses. An independent clauses─also known as a main clause─is a group of words that has a subject and a verb and can stand alone as a sentence. In the following example, the independent clauses are in brackets:
- [Miguel took piano lessons for sixteen years], and [today he is an accomplished performer].
The use of comma would also apply when any of the seven coordinating conjunctions (and, but, or, nor, for, so, yet) join two independent clauses.
Notice in the next example that we do not use a comma before "and" because it does not join two independent clauses but merely joins two verbs:
- Miguel took piano lessons for sixteen years and today is an accomplished performer.
Here we have only one independent clause─two verbs ("took: and "is") but one subject("Miguel").
Keep in mind that length is not a factor in determining when to use the comma before a coordinating conjunction. In this next example, even though the sentence is long, we do not need a comma because we have only one independent clause. ...
- Sigfried wanted to go back to school to earn a college degree but could not afford to quit his job and lose his health care benefits.
Since commas are used in pairs to enclose phrases that interrupt a clause or that are intended to function parenthetically, a writer may choose to place a comma before "and" (or any of the seven coordinating conjunctions) when the conjunction launches such a phrase:
- Sarah told him again, and really meant it this time, to turn off the television.
- Alice will ask John once, but only once, to forgive her.
TEST YOURSELF ( ... ... )
자료 2. Comma Before And
자료 3. Should I use a comma before “and” or “or”?
자료 4. Comma Between Compound Subject and Predicate
A compound subject is a subject which lists more than one thing. Commas may be used within the compound subject to separate the nouns, but should not be used between the subject and the predicate of the sentence.
- Some frequent causes of headaches are(,) stresses, lack of exercises and dehydration.
The comma between ^are^ and ^stress^ should be removed because it separates the predicate from the subject. The other comma is grammatically correct.
- Literacy and good writing skills(,) are necessary in most careers.
- Time and space(,) are fascinatingly fields of study.
자료 5. Unnecessary Comma in a Complex Sentence
Complex sentences are sentences which have two clauses. There can be two independent clauses (each having a subject and predicate), or an independent clause and a dependent clause (missing a subject or predicate). Generally, if the dependent clause comes second, a comma is not used before the dependent [meaning subordinate?] clause. Frequently, but not always, a conjunction will begin the dependent clause. ( ... ... )