1. Use a comma before the conjunction (and, for, but, or, nor, so) that joins the two independent clauses in a compound sentence.
Examples: I like working outside, and I also enjoy reading.
Matthew got out of school early, so he took a nap.
2. Use a comma after a relatively lengthy introductory phrases or dependent (subordinate) clauses. It is important to note that a comma should not be used when the clause or phrase come at the end of the sentence as illustrated by the third example.
Examples: In order to be successful, one must learn to write well.
After Peter learned the rules for using commas, his grades improved.
Sang won’s grades improved after he learned to use commas correctly.
3. Use commas to separate items in a series. Be sure to insert a comma before the conjunction that precedes the last item unless your teacher or style manual specifically tells you to exclude them.
Example: Timothy ordered six hamburgers, a Coke, an apple pie, and a large order of
fries.
4. Use commas before and after non-essential elements (parts of the sentence providing information that is not essential in order to understand its meaning.)
Example: Boston Trinity Academy, which is the only Christian school in the
district, enrolls only 208 students.
Examples: By the end of the game the field was a slippery, wet mess.
Justin’s big blue eyes and bright red hair made him strikingly handsome.
6. Use commas to separate the elements of dates and places.
Examples: Willie was born on December 8, 1996
Zach lives in Randolph, Massachusetts.
7. Use a comma before a direct quotation. Also, as shown in the example, commas (and periods as well) go inside the quotation marks.
Example: When asked if he had studied for the quiz Alex replied, “A whole lot,”
8. Use commas before and after words and phrases like however and never the less that serve as interrupters.
Example: Daniel did not like math. He was, however, very successful in his math
classes.
Semi-Colon Rules
1. Use a semi-colon in place of the comma and conjunction to separate the two independent clauses in a compound sentence.
Example: Siwon likes running outside; He also enjoys singing.
2. Use a semi-colon before the conjunctive adverb (such as however and therefore) that joins two independent clauses. Be sure to put a comma after the conjunctive adverb.
Example: Bumi likes dancing outside; however, he also enjoys sleeping.
3. Use semi-colons to separate elements in a series if they contain internal punctuation.
Example: When they ran to the end zone, Tevin and Tariq found red, blue, and
green circles; pink, purple, and orange squares; and a few black diamonds.
On their apple-picking trip, Chris and Nathan collected McIntosh, Macoun,
and Granny Smith apples; spaghetti, acorn, and butternut squash; and a few
large pumpkins.
