The quick thinker thought quickly during the test.
The: Article (Adjective)
Quick: Adjective (describing the noun "thinker")
Thinker: Noun (the subject)
Thought: Verb (the action)
Quickly: Adverb (describing how the thinker thought)
During: Preposition (showing the relationship between thinking and time)
The test: Noun (object of the preposition)