I’ve had a few questions about the passive. We went through that maybe a little quickly in class, and a while ago. The main thing to know about the passive is that, in a passive sentence, there is a Pass auxiliary (“be”) which has, as a condition, that the vP in its complement not have a specifier. No Agent. A passive sentence does not have an Agent in the usual way, it is more like an unaccusative verb. So, where John is the Agent and the sandwich is the Theme, in John kicked the sandwich, the passive form can be just The sandwich was kicked, with the Agent removed and Theme “promoted” to become the subject.

When you include the Agent in a by-phrase, you can take this to be a normal PP, just like by the barn would be. Headed by the P by, with a DP complement. Now, a normal PP would be adjoined in the structure either at vP or at TP, depending on what the meaning is. An agentive by-phrase might attach differently; there is a slide on the handout (“Where does the by-phrase attach?” on handout 10a) that provides data suggesting that the by-phrase attaches lower than TP-adverbs and higher than vP-adverbs. The conclusion of this (which was said in class, though not included on the handout itself) is that the by-phrase probably adjoins to PassP, since that’s what there is between TP and vP. I’ve drawn a (schematic) picture below.