Here's why:
* All sentences need a verb: This is the action or state of being.
* Sentences can be as simple or complex as needed: You might have a sentence with only a noun and a verb (e.g., "Birds fly."), or a sentence with many different parts of speech like nouns, verbs, adjectives, adverbs, conjunctions, etc.
The eight major parts of speech in English are:
1. Nouns: Names of people, places, things, or ideas (e.g., cat, house, love)
2. Pronouns: Replace nouns (e.g., he, she, it, they)
3. Verbs: Show actions or states of being (e.g., run, eat, think, be)
4. Adjectives: Describe nouns (e.g., blue, happy, small)
5. Adverbs: Describe verbs, adjectives, or other adverbs (e.g., quickly, very, beautifully)
6. Prepositions: Show the relationship between a noun or pronoun and another word in the sentence (e.g., on, in, under, over)
7. Conjunctions: Join words, phrases, or clauses (e.g., and, but, or, so)
8. Interjections: Express strong emotions (e.g., Wow! Ouch! Help!)
Therefore, a sentence can use any number of parts of speech, but it must have at least a noun and a verb to be a complete sentence.