I'm reading "Introduction to English linguistics" and in the chapter 4, there is a paragraph that I don't understand :
The other crucial cluster of properties of heads concern their structural relation to the other constituents. Thus, in verb phrases and prepostional phrases the head assigns case to the constituent to its right, which is the reason why we find "him" instead of "he", and "her" instead of "she" in
I saw him/ *he (wrong) yesterday
I met her /*she yesterday
This was a surprise for him / *he
This was a surprise for her / *she
Does anyone can explain to me ?