Final answer:
The best replacement for the underlined words is 'to hope' as it maintains parallel structure and matches the future context of the sentence.
Step-by-step explanation:
The best replacement for the underlined words in the sentence is to hope. By using the infinitive form 'to hope', it maintains parallel structure with the previous verb 'to study' and is grammatically correct. The use of 'one day' suggests a future action, so the infinitive form is the appropriate choice.
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