Final answer:
The phrases 'I could and would work hard to improve my situation' and 'Now I wear a pin on my lapel that says "Freshman Class President."' best exemplify the optimistic, purposeful tone of the story, suggesting determination and successful accomplishment.
Step-by-step explanation:
The two phrases that best support the optimistic, purposeful tone of the story are: 'I could and would work hard to improve my situation' and 'Now I wear a pin on my lapel that says "Freshman Class President."' These expressions demonstrate determination and a positive outlook on achieving goals. The first phrase highlights the character's commitment to effort and personal growth, which carries a hopeful undertone. The second phrase illustrates the accomplishment of a leadership role, implying success and fulfillment of purpose that align with an optimistic tone.