Diagnostic: Constituent Structure
Halliday & Matthiessen (2004: 240n):
Ascriptive verbs of marked phase such as turn and look, were treated as ‘intensive’ even when they had a preposition after them: for example, caterpillars turn into butterflies, Penelope looked like an angel. This reflects their constituent structure; cf what they turn into are butterflies (not what they turn is into butterflies), Penelope looked angelic. But there is an overlap at this point, and these could also be interpreted as circumstantial.