The caffeine content of coffee varies greatly, depending on the beans, how they're roasted, and other factors, but the average for an 8-ounce cup is about 100 milligrams (mg).
No, 'cat' is a common noun, a word for any cat of any kind. A proper noun is the name of a person, a place, a thing, or a title; for example: Cat Deeley, host of TV series 'So You Think You Can Dance'.
GRADE 4 GRAMMAR REFERENCE GUIDE Pre-Unit 1: PAGE 18 OF 21 19. Proper Nouns Proper nouns are the names of particular people, places, and things. They always begin with a capital letter. In the following sentences, the proper nouns are in gray.