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'.
Your name is a proper noun. A proper noun is the special word that we use for a person, place or organization, like John, Marie, London, France or Sony. A name is a noun, but a very special noun - a proper noun. English proper nouns have special rules. In this lesson we look at the uses of proper nouns: