Answer:
The correct answers are: infinitive phrase; adjective.
Explanation:
The phrase we are looking at is <em>to write about; </em>given that it contains and infinitive, we can safely assume it's an infinitive phrase. Now, given that it modifies, or describes a noun, it means that it acts as if it were an adjective.
Since adjectives are words or phrases that modify nouns, the function of the infinitival phrase here is that of an adjective. It's not just any topic: it's the best topic <em>to write about.</em>
Based on the system of elimination, I would choose - the first is a fantasy but the second is reality (could really happen).
In the first sentence, the poet wishes that the trees are bent due to a boy playing there and swinging on the branches. But the second sentence shows a possible reality, where the cold weather is the one that destroys the birches.
