Final answer:
The statement uses a metaphor by describing the night air as 'fuel' for the speaker's work, suggesting that the fresh air invigorates and energizes the creative process.
Step-by-step explanation:
The figurative language used in the statement 'The night air was fuel for my work, and it was a beautiful night' is a form of metaphor. In this case, 'fuel' is not referring to a literal substance that powers machines but instead is used metaphorically to suggest that the night air is energizing the speaker's ability to work, as if providing sustenance or inspiration for their work. The use of 'fuel' in this way compares the night air to a source of nourishment that aids in the process of creation or productivity. The statement might also suggest an atmosphere that is conducive to focus and creativity, enhancing the overall work experience for the speaker.