A number of other punctuation marks are used less frequently, but still play important roles in English writing. Semicolons (;) are used to combine sentences into larger ones. Unlike the use of commas to combine very short sentences, semicolons are used for combining relatively longer sentences.

Semicolons are often used for combining sentences that are very closely related:

• The rising costs of medicines and medical equipment are large factors in making health insurance more expensive; employers cannot afford those costs, and they have to pass them on to employees.

Colons (:) are used at the beginning of lists of several or more items, or as a substitute for “it is, “they are,” or similar expressions:

• These are the major steps in applying for college: finding schools that have the major you want to study, filling out applications, asking for letters of recommendation, taking the SAT or ACT, and ordering official transcripts from your previous schools.
• There is only one thing to do: talk to your daughter’s teacher about it.

Parentheses () are used to say something that is important to the main message you are writing but is not an immediate part of it, something that would interrupt the flow of your writing if you didn’t keep it separate from everything else:

• Sang-hoon finished typing the report and saved multiple copies of it two hours after his supervisor gave the information to him (he types 85 words per minute).
• The overnight managers (Connie on weekdays, John on weekends) will prepare bakery goods, coffee, and tea before the morning shift arrives.