Exercise: choose the or blank to complete sentences.
"The" doesn't mean "all". In view of generalization, there are some rules:
1. We don't use "the" in generalizations with plural and uncountable nouns. 2. But, we use "the" when a description, such as with "of", follows the noun in rule 1. 3. We can use "the" in generalization with a singular countable noun to talk about a whole class.