I know that Hierarchy of Projections for VP is T > (Neg) > (M) > (Perf) > (Prog) > v > V, but what does this mean? Does it mean in a tree "T is always higher than Neg, and Neg is always higher than M"? I searched on Google but I'm still not able to figure it out. Can you give a brief explanation? Thank you in advance!:)
Indeed, the hierarchy T > (Neg) > (M) > (Perf) > (Prog) > v > V is in order of descending height in the verbal chain. If each type is present, TP will be above the others, then NegP will be its complement, MP the complement of that, etc, all the way down to VP being the complement of vP.
The parentheses indicate optionality. Under this framework, it might be that only TP, vP, and VP are present. In this case TP will have as its complement the first present thing further along the hierarchy: vP.