Final answer:
In the sentence from Eugene O'Neill's 'Beyond the Horizon,' the phrases that best complete the blanks, creating coherent and contrasting ideas between two characters, are 'in contrast,' 'however,' and 'nevertheless.'
Step-by-step explanation:
Which word or phrase best completes the sentence? In Eugene O'Neill's Beyond the Horizon, Robert, in contrast, wishes to seek adventure and travel the world. His brother, Andrew, however, is content to remain on the family farm. Nevertheless, Andrew does not understand Robert's dream to travel.