Commas Before Conjunctions:
* The "FANBOYS" Rule: You generally use a comma before a coordinating conjunction (for, and, nor, but, or, yet, so) *only* if it joins two independent clauses (complete sentences that could stand alone).
* Example: *The cat sat on the mat, and the dog chased a squirrel.*
* Not Always Necessary: You don't need a comma if the conjunction joins two words, phrases, or dependent clauses.
* Example: *The cat sat on the mat and a fuzzy blanket.*
Commas Before Prepositions:
* Generally No: You don't usually use a comma before a preposition.
* Example: *The cat sat on the mat under the table.*
Important Considerations:
* Clarity: Sometimes, a comma before a preposition can improve clarity, especially in longer or complex sentences.
* Example: *The cat, after a long nap, finally sat on the mat.*
* Series: If a preposition is used within a series, commas are used between the items in the series, but not before the preposition.
* Example: *The cat sat on the mat, under the table, and near the window.*
In Conclusion:
While there are general guidelines, the best approach is to consider the context and clarity of your sentence. If you're unsure, try reading your sentence aloud. If a pause feels natural before the conjunction or preposition, you might want to use a comma.