For example, if we change the tense of the verb to deliver (Figure 2) in delivered, the [VP [V delivers] NP] subtree will be transformed in [VP [VBD delivered] NP], where the NP is unchanged.
the similarity with the previous structure will be quite high as: (1) the NP with all sub-parts will be matched and (2) the small difference will not highly affect the kernel norm and consequently the final score.