Explain the use and the effect of the imagery and words specifically chosen by the poet in the poem On the grasshopper and the cricketThe poem is...

This poem was written in competition with Keats's friend
Leigh Hunt. They made up the topic and each had a go at a sonnet, which has a set
fourteen line structure usually divided into an octet (first 8 lines) and a sextet (last
six lines).  Keats leads off with the assertion of the first line and then gives a
supporting example from the summer followed by the winter.  Lines 2 through 8 are a
sizzling summer day -- even the birds are bothered -- but he shows a lively grasshopper
bouncing around happily in the shade of the grass.  The images make you really feel the
heat and sense the cool of the shade.  In the last lines he switches to the opposite --
winter -- it's cold and you're glad to have the heat of the fire.  And a cricket is also
there, sheltering near the fire, singing away.  In the last line he masterfully ties it
together by having a drowsy person near the fire think it's actually summer again,
coming back to the beginning in a kind of circle.  The imagery and the words are chosen
to be "sensual" -- so you actually can FEEL what he's talking about -- Keats's poetry is
like that.  Help?