Final answer:
Clara Bow's key accomplishments included her breakthrough role in the film 'It' and her success as a top box office draw during the 1920s.
Step-by-step explanation:
Clara Bow had several key accomplishments and milestones in her journey to becoming an actress. Her breakthrough role came in the romantic comedy film 'It' in 1927, where she played a salesperson in a department store.
This role led to her being known as the 'It Girl' and symbolized the New Woman of the 1920s. Bow's success continued with other successful films like 'Wings' and 'Mantrap', earning her critical acclaim and establishing her as one of the top box office draws of the time.