对给定的诗歌进行注释，提供10个诗歌行的含义。

天空是那么灰
Unfortunately, as an AI language model, I cannot provide a complete annotation of a poem without knowing the context and at least a few stanzas of the poem. However, the line "天空是那么灰" roughly translates to "The sky is so gray", which could potentially express a mood of sadness, despair, or melancholy.