When should one use the comma versus the semicolon, and vice versa?

Question

I cannot understand the difference between the comma and semicolon. Can you please clarify?

Answer 1

From eHow:

Comma (,)

1) Use a comma to separate 2 independent clauses joined by a coordinating conjunction such as and, but and or. The key here is to have 2 subject verb pairs.

Example: The students reviewed for the exam, and the teacher corrected the term papers.

In this example we have 2 subject verb pairs: "students reviewed" and "teacher corrected."

Example: The teacher corrected the papers and entered the grades in the grade book.

In this example we use the coordinating conjunction "and" but have 1 subject and 2 verbs: "teacher corrected, entered"; therefore, no comma is used.

2) Use a comma to separate items in a series to avoid ambiguous meaning.

Example: Uncle willed me his property, houses, and warehouses.

In this example, we mean that uncle willed me 3 items--his houses, warehouses, and property.

Example: Uncle willed me his property, houses and warehouses.

In this example, we mean that uncle willed me 2 items--all his property, which consisted of houses and warehouses.

3) Use a comma with introductory elements such as subordinating clauses that come at the beginning of the sentence.

Example: Because the river had flooded, the school closed for the week.

The introductory element, or subordinating clause is "because the river had flooded." It is introduced with the subordinating conjunction "because."

Example: The school closed for the week because the river had flooded.

In this example the subordinating clause is at the end of the sentence so we do not use a comma.

Semicolon (;)

1) Use a semicolon to separate 2 independent clauses in a sentence, closely related, with no coordinating conjunction.

Example: The students reviewed for the exam; the teacher corrected the papers.

Example: The candidates spoke to the crowds during Election Day; each candidate spoke passionately about the fate of the country.

2) Use a semicolon to separate items in a series where the series themselves contain commas.

Example: We visited our relatives in Albany, NY; Philadelphia, PA; and Washington, D.C.

Answer 2

You use a semicolon (;) to create a compound sentence made of two complete sentences. For example: John went to school; today was his first day. is equivalent to John went to school. Today was his first day. and so is correct.

Use of a semicolon is inappropriate in any other case. The following is incorrect: Because John went to school; Sally was left home alone. because if we split into two sentences, Because John went to school. Sally was left home alone., the first is a sentence fragment.

In addition, use of a comma to separate two complete sentences (John went to school, today was his first day.) is inappropriate and is called a comma splice.

Answer 3

The first is a comma, which is just a pause that off-sets a phrase. The second is a semi-colon, "used to indicate a major division in a sentence where a more distinct separation is felt between clauses or items on a list than is indicated by a comma, as between the two clauses of a compound sentence."