For example:
*He painted her sitting on the step.Here the participial phrase sitting on the step may be intended to modify her (meaning that the painting's subject was sitting on the step), or it may be intended to modify the verb phrase painted her or the whole clause he painted her (or just he), meaning in effect that it was the painter who was sitting on the step.

Sometimes the element which the modifier is intended to modify does not in fact appear in the sentence, or is not in an appropriate position to be associated with that