The subject of a sentence can be a noun or pronoun.
An adverb describes an adjective.
The past participle of "lay" is "lain."
In the sentence: She is incredibly fast; "fast" is an adverb.
In the sentence: Have some boiled potatoes; "boiled" is the verb.
Adjectives describe nouns and pronouns.
In the sentence: Cake decorating is fun; "Cake" is the subject.
"Write" and "sing" are examples of irregular verbs.
"Ran" is the past participle of "run."
In the sentence: This test is timed; "timed" is the verb.