This document discusses common mistakes made with plural nouns in English. It explains the differences between countable and uncountable nouns, and how countable nouns form plurals while uncountable nouns do not. It provides examples of nouns that can be both countable and uncountable depending on meaning. It also covers nouns that are always plural, nouns ending in "s", group nouns, two-part nouns, and mistakes students often make with nouns. Exercises are included to practice identifying and correcting noun errors.