Grammar and Punctuation Rules

A semicolon (;) is a punctuation mark that combines the functions of both a period and a comma. It helps link closely related ideas or separates elements within complex sentences.

Linking related independent clauses: A semicolon can be used to connect two independent clauses (complete sentences) that are closely related in thought. It indicates a stronger connection than a period would, but not as strong as a conjunction.

• I have a meeting at noon; I have to prepare my presentation.

Both parts could stand as sentences on their own, but the semicolon shows that they are closely linked.
Before conjunctions in compound sentences: When you have a compound sentence with a conjunction (like however, therefore, for example, thus, etc.) that connects two independent clauses, a semicolon is often used before the conjunction, especially when the clauses themselves contain commas.

• She needs to study for her final exams; however, she still wants to spend time with her friends.

Separating items in a complex list: When a list of items has internal commas, a semicolon can help avoid confusion by clearly separating each item.

• On our trip, we visited Paris, France; Rome, Italy; and Barcelona, Spain.

The semicolons separate the different locations, each of which has a comma in its description.

Using a semicolon to separate an independent and dependent clause: Though independent and dependent clauses also need to be related, they are separated by a comma instead of a semicolon.

Incorrect:

• Although it's raining outside; we are going for a walk.

Correct: 

• Although it's raining outside, we are going for a walk.

Using a semicolon where a colon is needed: 

Incorrect:

• To build a chicken coop, you will need the following; wood (2x4s, 2x2s, plywood), hardware cloth or chicken wire, nails and screws, roofing materials, hinges and latches, and potentially nesting boxes, roosting bars, feeders, and waterers.

Correct:

• To build a chicken coop, you will need the following: wood, chicken wire, nails, screws, roofing materials, hinges, nesting boxes, roosting bars, feeders, and waterers.

Linking unrelated clauses:

Incorrect: 

• I love going to the trampoline park; my favorite color is blue.

Correct:

• I love staying active; the trampoline park is my favorite place. 

A colon (:) is a punctuation mark used to introduce or emphasize information. It often precedes a list, an explanation, or a clarification, and it signals that what follows is directly related to the idea or concept introduced before the colon.

Introducing a list: A colon is used to introduce a list of items after an independent clause (a complete sentence).

• The recipe calls for three main ingredients: cement, aggregates, and water.

The colon comes after the complete sentence ("the recipe calls for three main ingredients"), signaling that a list of items will follow.

Introducing an explanation or definition: A colon is used when you want to explain or define something mentioned before the colon. The part before the colon sets up a statement or idea, and what follows provides further detail or clarification.

• She had one goal in mind: to become a doctor. 

The clause before the colon introduces a concept (her goal), and the colon introduces the explanation of what that goal is.

Introducing a quote: A colon can be used before a long or formal quote, especially if the quote is introduced by a complete sentence.

• The professor made an important statement: "Turn your assignments in on time, or you will most likely fail the class."

Incorrectly introducing lists: 

Incorrect:

• The ingredients are: mayonnaise, honey, yellow mustard, BBQ sauce, and lemon juice.

Correct: 

• The ingredients are as follows: mayonnaise, honey, yellow mustard, BBQ sauce, and lemon juice.
• The ingredients are mayonnaise, honey, yellow mustard, BBQ sauce, and lemon juice.

Separating grammatical elements (like a verb and its object, a preposition and its object, or a subject and its complement): 

Incorrect:

• They enjoy: watching documentaries, reading blog posts, and running in the mountains.
• The cake is made of: flour, sugar, butter, and chocolate.

Correct:

• They enjoy watching documentaries, reading blog posts, and running in the mountains.
• The cake is made of flour, sugar, butter, and chocolate.

Incorrectly placed after introductory phrases or conjunctions (phrases like "such as," "including," "especially," or conjunctions like "and," "or," "but"): 

Incorrect: 

• There are many colors available, including: teal, chartreuse, lilac, and cerulean.
• He wanted to buy: a crossbody bag, a volleyball, and platform shoes.

Correct:

• There are many colors available, including teal, chartreuse, lilac, and cerulean.
• He wanted to buy a crossbody bag, a volleyball, and platform shoes.