Final answer:
The line 'These old bones live to learn her wanton ways:' uses metonymy, with 'old bones' representing the entire person and their life experiences.
Step-by-step explanation:
The line from Theodore Roethke's poem I Knew a Woman that is an example of the poetic technique metonymy is "These old bones live to learn her wanton ways:" In this line, "old bones" is used metonymically to stand in for the entire body or the person themselves, suggesting the aging process and the experience of life that the speaker has endured. Metonymy is a figure of speech in which a thing or concept is referred to by the name of something closely associated with that thing or concept.