* The pattern - This is the subject of the sentence, acting as a noun phrase.
* cautioned - This is the verb, indicating the action the pattern performed.
* that users - This is a clause acting as the object of the verb "cautioned."
* be sure - This is a verb phrase acting as the predicate of the clause "that users be sure."
* to choose - This is an infinitive phrase functioning as an adverb modifying "be sure."
* a fabric - This is the object of the infinitive "to choose."
* with marked bias - This is a prepositional phrase acting as an adjective modifying "fabric."
The part of speech playing a key role in this sentence is the verb "cautioned." It's what drives the sentence and sets up the rest of the information about the pattern's warning.
Let me know if you'd like a deeper dive into any specific part of the sentence!