The exciting force of Hamlet is the ghost's first appearance to Hamlet. Hamlet's encounter with his ghost father set the plot into action. Hamlet is informed by the ghost that Claudius, his uncle and now a Denmark ruler is one who murdered his father and to avenge for his death. This initial action unfolds the final tragedy.
Predicate nominative is also popularly known as the predicate noun. It is a noun, a pronoun or any nominal that follows the linking verb and most of the time the form of the verb be. It links or completes the linking and change the name of the subject. It complements or completes the verb in the sentence. However, predicate nominative completes only linking verbs. Predicate nominative can be compound while some do not have one. Therefore in the sentence "Sugar is the main ingredient in taffy", the predicate nominative is "ingredient".
Here's an example sentence.
The girl laughed as her father, the "fitness expert", struggled to do a push up.
This shows sarcasm and irony because if her father calls himself a fitness expert, then why is he struggling to do one pushup. This is the opposite of being a fitness expert.