Happy, striding and energetic fitness are adjectives. Adjective is a kind of part of speech, which is mainly used to describe or modify nouns or pronouns, indicating the nature, state, characteristics or attributes of people or things, and is often used as an attribute, as well as a predicate or complement.

Grammar is the law of grammar. When anyone uses a language, whether he has studied grammar or not, he must abide by it. In addition, summarizing the rules of grammar itself can also deepen our understanding of language and make us really proficient in using it. Grammar is an essential part to master standard English. Adjectives are also an indispensable part of English grammar.