Question

A comma should not be used to __________. separate compound elements set apart an introductory phrase separate narration from quotations set apart introductory words or interjections

Answer 1

A comma should not be used to separate compound elements. Compound elements should always be together, they cannot be separated by a comma. In the other cases, comma should be used.

Answer 2

A comma should not be used to SEPARATE COMPOUND ELEMENTS.
In English language, a compound word refers to a combination of two or more words that function together as one word. A compound word can be hyphenated or unhypenated. An example of unhypenated compound word is 'flowerpot' while 'well-being is an example of hyphenated compound word. The law of English grammar requires that compound words should not be used to separate compound words.