Final answer:
Commas are used after introductory clauses that precede independent clauses and to separate elements in a series, including before the final element if the Oxford comma is applied consistently. They also appear when coordinating conjunctions join independent clauses and after dependent clauses introduced by subordinating conjunctions before an independent clause.
Step-by-step explanation:
The use of commas in a sentence is vital for clarity and proper grammar. In the context of an introductory clause, a comma should be placed after the clause when it precedes the independent clause.
An introductory clause generally sets the stage for the main part of the sentence and is considered a dependent clause, as it cannot stand alone as a complete sentence.
Consider the following examples to understand the correct placement of commas:
- Before we leave, make sure to turn off the lights.
- Having finished the project early, we decided to celebrate.
- Though he was tired, he continued working.
In each of these examples, the comma comes right after the introductory clause, which contains a subject and verb but does not express a complete thought without the main part of the sentence.
An important point to note is when dealing with a series of three or more items, commas should be used to separate them. The use of the Oxford comma—the comma before the 'and' or 'or' in a series—is optional but recommended for clarity. It should be consistently used or omitted throughout a piece of writing.
For instance, 'The picnic basket contained sandwiches, apples, and lemonade.' Here, the Oxford comma is used before 'and' to prevent any confusion.
Commas with Coordinating and Subordinating Conjunctions
Commas are also used with coordinating conjunctions—For, And, Nor, But, Or, Yet, So (FANBOYS)—to join two independent clauses.
An independent clause is a group of words that can stand alone as a sentence. If the sentence has more than one independent clause, they can be connected with a comma followed by a coordinating conjunction, as in 'She loves to read, and she frequents the library regularly.'
When using subordinating conjunctions such as 'although', 'because', and 'if', a comma must be placed after the dependent clause if it comes before the independent clause, but not necessarily when it follows it.