1. Commas after periods:
* Generally, no. A period usually marks the end of a sentence, and you don't put a comma after the end of a sentence.
* Example: "The cat sat on the mat. It looked very content."
2. Commas after other punctuation marks:
* Semicolons: A comma is not used after a semicolon.
* Example: "The meeting went well; everyone seemed happy."
* Colons: A comma is not used after a colon.
* Example: "There were three main points: first, the budget; second, the timeline; and third, the team."
* Question marks: A comma is not used after a question mark (unless it's part of a series of questions).
* Example: "Did you see the movie? I thought it was great."
* Exclamation points: A comma is not used after an exclamation point.
* Example: "Look out! That car is coming!"
3. Commas within a sentence:
* Parentheses: A comma is not used after a closing parenthesis unless it's grammatically required.
* Example: "The cat (a tabby) sat on the mat."
* Dashes: A comma is not used after a dash (unless it's part of a series of items).
* Example: "The cat—a tabby—sat on the mat."
* Quotation marks: A comma is placed inside the closing quotation marks if it's part of the quoted material.
* Example: "The cat sat on the mat," he said.
In Summary:
* Commas after periods are generally not used.
* Commas are not typically used after other punctuation marks, except in very specific cases.
* Commas are placed within other punctuation marks if required by grammar.
If you are ever unsure, it's always best to consult a style guide or grammar reference book.