Verb means the action of the sentence, the action going on is 'ate', so that is the verb.
You did not provide the excerpt but in the end Jekyll was not able to permanently resist. It was implied that he was actually Hyde deep inside and that Hyde is the one who will overtake and he won't be able to come out again. In the end he dies as Hyde and people find out what happened out of letters that he sent while he was sane.
The king and queen summoned them to Elsinore in hope they can cheer Hamlet out of his melancholy
Shakespeare did get his ideas from nature and the day to day events. Being a critical and creative thinker he was able to write a number of literature materials.