Correct comma usage involves placing them before coordinating conjunctions joining independent clauses, after introductory clauses or phrases, and in a series. Some commas are to be omitted if they precede the conjunction in a compound predicate or if they separate a dependent clause from the rest of the sentence.
Correctly punctuating sentences is crucial in ensuring the clarity of the writing. Here, we'll apply proper comma usage to the provided sentences.
I finally found my keys, and I got to work just in time.
Mrs. Contreras threw out her old coffee table, and cleaned the carpet.
Taking the elevator to the roof, we hoped we could see the skyline, and the bay.
Though Susan wasn't feeling well, she went to the store anyway and bought ice cream, pizza, and candy.
Omit the comma: I let my neighbor borrow my phone because she said hers was tapped by the police.
In sentence 1, the comma before 'and' is necessary because it connects two independent clauses. In sentence 2, the comma after 'table' is removed because it is not needed before 'and' when it joins a compound predicate. Sentence 3 requires a comma after 'roof' as it is an introductory clause and another after 'skyline' to separate items in a series.
Sentence 4 needs a comma after 'well' to separate the introductory clause and another after 'ice cream' as part of the series. Sentence 5 does not require a comma as it is a dependent clause providing a reason, not an independent clause.