The dog runs fast.
Noun: dog
Verb: runs
Adjective: fast
Article: the
She is happy today.
Pronoun: she
Verb: is
Adjective: happy
Adverb: today
Wow! That is a big house.
Interjection: wow
Pronoun: that
Verb: is
Adjective: big
Noun: house
I learned that each part of speech helps make a sentence clear and easy to understand.