The Syntax-Augmented MT model of Zollmann and Venugopal (2006), for instance, produces a very large nonterminal set using "slash" (NP/NN → the great) and "plus" labels (NP+VB → she went) to assign syntactically motivated labels for rules whose target words do not correspond to constituents in phrase structure parse trees.
the true score of each translation is "fragmented" across many derivations, so that each translation's most probable derivation is the only one that matters.