if we form the passive of break (= broken), the subject (or external argument) is demoted to become an adjunct (= the by-phrase):
(i) Tom broke the vase (ii) The vase was broken (by Tom)
- Marantz, A. 1984. On the Nature of Grammatical Relations, Cambridge, Mass., MIT Press.
- Spencer, A. 1991. Morphological Theory, Blackwell, Oxford.
- Williams, E. 1981b. Argument Structure and Morphology, The Linguistic Review 1, pp. 81-114