Analysis of Song [When I am dead, my dearest]

When I am dead, my dearest,
    Sing no sad songs for me;
Plant thou no roses at my head,
    Nor shady cypress tree:
Be the green grass above me
    With showers and dewdrops wet;
And if thou wilt, remember,
    And if thou wilt, forget.

I shall not see the shadows,
   I shall not feel the rain;
I shall not hear the nightingale
   Sing on, as if in pain:
And dreaming through the twilight
    That doth not rise nor set,
Haply I may remember,
    And haply may forget.