Final answer:
A potential pairing for a poem by Tu Fu that matches the subject and mood of Wordsworth's 'Upon Westminster Bridge' could entail reflective contemplation of peaceful moments within chaotic times, mirroring Wordsworth's serene appreciation of a usually bustling city at dawn.
Step-by-step explanation:
Identifying a pairing of poems that exhibit a close unity of subject and mood between English Romantic poets and Tu Fu, a Tang dynasty poet, is a nuanced endeavor. Looking at the description of the city in William Wordsworth's Upon Westminster Bridge, which presents a unique Romantic appreciation of a cityscape, we can discern that Wordsworth breaks away from typical Romantic disdain for urban environments, instead finding beauty within the early morning tranquility of London. This presents a subject matter focusing on a physical setting imbued with emotion, hinting at an unconventional harmony of human construction and the natural world.
In Tu Fu's poetry, we find a deep sense of personal emotion and contemplation of the poet's surroundings, often expressing themes of harmony despite distress or warfare. A poem by Tu Fu that might pair well with Wordsworth's Upon Westminster Bridge in terms of subject and mood could be one that expresses a reflective tone and appreciation for a particular setting, perhaps during a moment of peace in otherwise tumultuous times.
Without a specific poem from Tu Fu provided in the question, a direct comparison is challenging; nonetheless, the essence of both poets' works often illustrate a contemplative observation of their surroundings from which a reader can extricate a sense of serene beauty or thoughtful calmness amidst the broader complexities of life.