In English, nouns are "countable" or "uncountable." Countable nouns refer to things and concepts that can be counted, like two hours, five puppies and twenty geraniums. Uncountable nouns refer to things and concepts that cannot be counted, such as luggage, information or courage.
Although identifying countable and uncountable nouns sounds easy, it isn't always so—sometimes, the same noun can have both a countable and uncountable sense. Think of time, as in we've had some good times (countable) versus it's time to leave (uncountable).
In the following sentences, identify whether the nouns in square brackets are countable or uncountable.