When driving in the mountains, you will often see signs along the street that warn drivers about falling rocks.
The direct object in this sentence is "us." The verb "warned" is directly affecting "us" by giving them a warning to stay on the ranch.
Warned has no prefixes or suffixes.
The past participle of "warn" is "warned."
My co-worker noticed that I don't enjoy taking orders, and he warned me to be more subservient to our boss.
He deviated away from the group's plan, and told them off in a brash voice.
The nouns in the sentence are: sign, drivers, rocks, and street.
The verb is "warned." It's the past tense of "to warn." But be advised that some signs do not have verbs at all: they just have fragments like "no passing" or "school zone." And as others on this page have noted, "falling" can be a verb, but in the sentence you asked about, it is not--it's an adjective that describes "rocks."
Drivers were warned of the adverse camber on the bend by the road signage.
Phineus.
jessica always warns me about my future.
The direct object in this sentence is "us." The verb "warned" is directly affecting "us" by giving them a warning to stay on the ranch.
The captain warned the lookouts to be extra vigilant as a radio signal warned of possible enemy ships ahead.
The mother warned the daughter not to compromise her values.
The TV weather man warned that a storm, approaching from the west, was imminent.
The commanding officer warned his troops not to pillage the conquered city.
The sign on the highway warned that you must yield to other vehicles.
The soothsayer warned Captain Bob not to travel the Atlantic Ocean for it is stormy.