Modern American writers generally use punctuation so their readers can understand their writing. The old rules concerning punctuation have become guidelines. Your reader is more important than the rules. Will the comma or the lack of it clarify the issue to your reader. For example, you can put commas this way. John and Sue, Bill and Mary, and Jane went fishing. Your readers already know John and Sue are couples and Jane is single. The commas divide the elements that go together. The comma before the final "and" indicates that it is the last item in the series. We could have said, "and Jane and Joan. the first and would have the comma in front of it. Write your sentence. Then look at it. Have an eraser. Use a pencil. Try it both ways.
last comma before the and is not necessary
You went swimming, rock climbing, and skating last week. (The second comma is optional, I just prefer it. But if you only need one comma then you can leave it out.)
you do not have to put the comma there
You can use ", and" or just "and" but not just a comma.
Yes, there is a comma after "Last Saturday" if it is used at the beginning of a sentence or an introductory phrase. For example: "Last Saturday, we went to the park." However, if "Last Saturday" appears in the middle of a sentence, a comma may not be necessary.
no
it needs a comma
If it is the last word in the sentence than yes you would use the comma. Commas are so you could take a little rest between words. Examples: I like cotton candy, too! Your at this park, too? I can't believe you did this to me, too! You gossip, too?
A comma splice is the attempt to join two independent clauses with a comma without a coordinating conjunction. For example, "She walked the dog last night, today she fed it."
"In five years, things happened." Yes you do need a comma.
No. There is no word in English that always requires a comma before it.
No, you do not typically put a comma between a person's last name and their suffix (e.g., Jr., Sr., III). You would write the full name without a comma between them.