Suggested answer for Exercise 4

The sentence in the sentence John sent a message to Mary is traditionally called the dative construction. The main verb send is in the V head and assigns a theme thematic role to the DP a message in the specifier of the VP and a goal thematic role to its complement PP. The vP is an extended projection of the VP, so the main verb assigns an agent thematic role indirectly via the v to the DP in the specifier of the vP. The DP Mary receives accusative Case from the preposition to while the DP a message gets its accusative Case from the v head. Since the light verb is a bound morpheme, the main verb adjoins to the v head and then moves on to the tense v and I to agree with the subject. The DP in the specifier of the vP needs to be assigned Case as well, so it has to move to the specifier of the IP.