No, before ... as in: Marcus Welby, MD
Yes. You should write it at John P. Doe, MD
Not necessarily. Commas are a feature of sentence structure.
A run-on sentence occurs when two independent clauses are connected without proper punctuation or conjunctions. A comma splice, on the other hand, happens when two independent clauses are incorrectly joined with a comma but without a coordinating conjunction. Both errors result in choppy or confusing sentences.
Between everyone in a business, the Chairman is the top dog. Between the MD and CEO, however, the MD is the superior office, with the CEO reporting to the MD.
NO. You replace the comma with "of"... For instance, July of 2009
Baltimore, Maryland is located between Gaithersburg and Severn.
The halfway point between Manchester, Md and Elkridge, Md falls around the Northwest Expressway in Owings Mills, MD.
The comma goes between the day and the month and between the number and the year: Wednesday, June 5, 2012.
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."
A comma splice occurs when two independent clauses are connected with only a comma. To identify a comma splice, look for two complete sentences joined together with a comma without a coordinating conjunction (and, but, or, etc.) or a semicolon. Fix a comma splice by adding a coordinating conjunction, replacing the comma with a semicolon, or using a period to make separate sentences.
The best guide is to put a comma when there is a short gap between the words when spoken.