Helen grey
by christina georgina rossetti

because one loves you, helen grey,
is that a reason you should pout,
and like a march wind veer about,
and frown, and say your shrewish say?
don't strain the cord until it snaps,
don't split the sound heart with your wedge,
don't cut your fingers with the edge
of your keen wit; you may, perhaps.

because you're handsome, helen grey,
is that a reason to be proud?
your eyes are bold, your laugh is loud,
your steps go mincing on their way;
but so you miss that modest charm
which is the surest charm of all:
(take heed, you yet may trip and fall,
and no man care to stretch his arm.) < -- bold

stoop from your cold height, helen grey,
come down, and take a lowlier place;
come down, to fill it now with grace;
come down you must perforce some day:
for years cannot be kept at bay,
and fading years will make you old;
then in their turn will men seem cold,
when you yourself are nipped and grey.

in what way do the lines in bold support the main theme of the poem?

use evidence from the poem to support your answer.