The most common punctuation mark in the English language is the period. Every sentence requires one to mark its end. Commas, colons, and semicolons are also common punctuation marks. These three punctuation marks are used to mark pauses in sentences, and as a result are commonly confused.
Commas are used in lists between items and in compound sentences they are used before the conjunction. A semicolon is used to connect two closely related, independent clauses. A colon is used before an explanation, example, or series. Apostrophes are common, and used to indicate contractions and are also used in possessive nouns and pronouns. Hyphens, parentheses, and quotation marks are also very commonly used punctuation marks in English grammar.