Article

Writers sometimes struggle with the choice to include an article or to leave it out altogether. Keep in mind that if the noun is singular, countable, and nonspecific or generic (e.g., book, author), the articles "a" and "an" may be used. However, if the noun is countable and plural (e.g.., "research studies") or uncountable (e.g., "information") and it is being used in a nonspecific or generic way, no article is used.

Here are some more specifics:

No article is used when a plural countable noun is generic or nonspecific.

• I bought new pens and pencils at the store. (general, not specific ones)
• Cats have big eyes that can see in the dark. (cats in general, all of them)
• Babies cry a lot. (babies in general, all of them)
• No article is used when a noncount noun is generic or nonspecific.
  • I bought milk and rice at the store. (generic reference)
  • We were assigned homework in this class. (generic reference)
  • There has been previous research on the topic. (generic reference)