I think it is important for everyone to understand the extent to which First-Class mail is already carrying a disproportionate share of the institutional cost or overhead burden of the postal system.
( I ( ( think ( it ( ( is ( important ( for everyone ) ) ) ( to ( understand ( ( the extent ) ( ( to which ) ( ( First-Class mail ) ( ( is already ) ( carrying ( ( a ( disproportionate share ) ) ( of ( ( the ( institutional ( cost ( or ( overhead burden ) ) ) ) ) ( of ( the ( postal system ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (PRP I)) (VP (VBP think) (SBAR (S (NP (PRP it)) (VP (VBZ is) (ADJP (JJ important) (PP (IN for) (NP (NN everyone)))) (S (VP (TO to) (VP (VB understand) (NP (NP (DT the) (NN extent)) (SBAR (WHPP (TO to) (WHNP (WDT which))) (S (NP (NNP First-Class) (NN mail)) (VP (VBZ is) (ADVP (RB already)) (VP (VBG carrying) (NP (NP (DT a) (JJ disproportionate) (NN share)) (PP (IN of) (NP (NP (DT the) (JJ institutional) (NN cost) (CC or) (NN overhead) (NN burden)) (PP (IN of) (NP (DT the) (JJ postal) (NN system)))))))))))))))))) (. .)))
We need to understand they have a lot of burden on their shoulders.
( We ( ( need ( to ( understand ( they ( have ( ( a lot ) ( of ( burden ( on ( their shoulders ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (PRP We)) (VP (VBP need) (S (VP (TO to) (VP (VB understand) (SBAR (S (NP (PRP they)) (VP (VBP have) (NP (NP (DT a) (NN lot)) (PP (IN of) (NP (NP (NN burden)) (PP (IN on) (NP (PRP$ their) (NNS shoulders))))))))))))) (. .)))