Interrupting phrases that add contextual information but do not fundamentally alter the grammatical structure of the sentence must be separated from the rest of the sentence by commas. In the sentence above "Cicero a one time senator" should read, "Cicero, a one time senator," instead. 

Interrupting phrases are phrases that add information to a sentence, but are not necessary to the sentence being complete, and they must be separated from the rest of the sentence by commas. In the sentence above "Paul the fireman's son was hurt" should read, "Paul, the fireman's son, was hurt."

Interrupting phrases, subordinate phrases that add information to a sentence but are not necessary to the sentence being complete (like this one), must be separated from the rest of the sentence by commas. The best way to correct the underlined portion above is: "Spencer, one of the most boorish men I have ever met, is really no fun to be around."

Introductory or interrupting phrases are phrases that are subordinate and add information to a sentence, but are not necessary to the sentence being complete. Introductory and interrupting phrases must be separated from the rest of the sentence by commas. The best way to correct the underlined portion above is: "The novel we're studying, one of my favorite books of all time, has recently developed a new fan base."

Introductory or interrupting phrases are phrases that are subordinate to the main clause and add information to a sentence, but are not necessary to the sentence being complete. Introductory phrases must be separated from the main clause by a comma. The best way to correct the underlined portion above is: "When you fail to pay attention during the seminars, you're only hurting yourself."

Introductory or interrupting phrases add information to a sentence, but are not necessary to the sentence being complete. Since they are dependent clauses, they must be separated from the rest of the sentence with a comma. The best way to correct the underlined portion above is: "My favorite dish, pork fried rice, is"

Interrupting phrases provide context or information about an element of the sentence, but are not necessary to the sentence being grammatically complete, therefore they must be separated from the rest of the sentence by commas. The best way to correct the underlined portion above is: "Michael, the youngest boy on the trip, because"

Phrases that are subordinate and add information to a sentence but are not necessary to the sentence being complete must be separated from the rest of the sentence by commas. If these phrases come in the middle of the main clause they are called interrupting phrases. The best way to correct the underlined portion above is, "I don't much care for Marcus, easily the most pugnacious player on our team, because he is such a poor sport."

Introductory or interrupting phrases, phrases that are subordinate and add information to a sentence but are not necessary to the sentence being complete (like this one!), must be separated from the rest of the sentence by commas. You should be able to remove an interrupting phrase from a sentence without grammatically altering the overall structure of the sentence. The best way to correct the underlined portion above is, "Bourbon County, one of the most famous counties in all Kentucky, is widely known for its history and culture."

Introductory phrases come at the beginning of a sentence. They are subordinate and add information or context to a sentence, but are not necessary to the sentence's grammatical completeness. Introductory phrases must be separated from the rest of the sentence with a comma. The best way to correct the underlined portion above is, "After she took her terrible fall, the very old woman had great difficulty walking around."