We've been a couple of mutts, who've bitten off a bigger bit than they can chew.
( We ( ( 've ( been ( ( a couple ) ( of ( ( mutts , ) ( who ( 've ( ( ( bitten off ) ( a ( bigger bit ) ) ) ( than ( they ( can chew ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (PRP We)) (VP (VBP 've) (VP (VBN been) (NP (NP (DT a) (NN couple)) (PP (IN of) (NP (NP (NNS mutts)) (, ,) (SBAR (WHNP (WP who)) (S (VP (VBP 've) (VP (VBN bitten) (PRT (RP off)) (NP (DT a) (JJR bigger) (NN bit)) (SBAR (IN than) (S (NP (PRP they)) (VP (MD can) (VP (VB chew)))))))))))))) (. .)))
We can definitely manage what we've started.
( We ( ( ( can definitely ) ( manage ( what ( we ( 've started ) ) ) ) ) . ) )
(ROOT (S (NP (PRP We)) (VP (MD can) (ADVP (RB definitely)) (VP (VB manage) (SBAR (WHNP (WP what)) (S (NP (PRP we)) (VP (VBP 've) (VP (VBN started))))))) (. .)))