(a) In the poem, the "empty forest" likely refers to a forest that lacks life and activity due to the absence of trees. Trees are a crucial part of a forest ecosystem, providing habitat for birds, insects, and other wildlife, and influencing light and shadow patterns. The forest is described as empty because it lacks these essential elements, creating an image of a barren or lifeless place. (b) The line "No sun bury its feet in shadow" is a poetic way of describing the absence of shadows cast by trees. In this metaphor, the 'feet' of the sun could represent its rays that touch the earth. When there are trees, the sun's rays create a play of light and shadow on the forest floor. Without trees, there are no shadows for the sun's 'feet' (its rays) to 'bury' themselves in. (c) Another word for “put or hide underground” is "bury". This word conveys the idea of placing something beneath the ground or concealing it within the earth.