Ergative verbs and the passive
Ergative verbs and the passiveIn patterns where there is a noun group (the Object) following the verb, the 'causer' is indicated by the Subject and the 'doer' is indicated by the Object. In the equivalent passive structure, however, the 'doer' is indicated by the Subject and the 'causer' may not be mentioned. Compare the following examples:
The third example is the passive of the second example. We said above that in the first example, you may understand that the vase broke by itself or that someone caused the vase to break, whilst in the second example, you understand that John caused the vase to break. In the third example, you understand that the vase did not break by itself, but do not know who caused the breakage. The Subjects of the first and the third examples are the same, but the meanings are different.
The vase broke.
John broke the vase.
The vase was broken.