Suggested answer for Exercise 4

In the sentence John sank Jim’s boat the theme argument is in the specifier of the VP, while the agent occupies the specifier of the vP in the D-structure. In the S-structure, the agent DP has to move to a position where Case can be assigned to it. This position is the specifier of IP. The main verb sink has to move as well since the abstract light verb e is a bound morpheme, which requires the main verb to move to v, tense v and then to I.