( ( Most craters ) ( ( ( ( have ( been ( filled ( with water ) ) ) ) and ) ( have ( become ( ( ( lakes and ) others ) ( have ( fallen ( into ( the ocean ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (JJS Most) (NNS craters)) (VP (VP (VBP have) (VP (VBN been) (VP (VBN filled) (PP (IN with) (NP (NN water)))))) (CC and) (VP (VBP have) (VP (VBN become) (SBAR (S (NP (NNS lakes) (CC and) (NNS others)) (VP (VBP have) (VP (VBN fallen) (PP (IN into) (NP (DT the) (NN ocean)))))))))) (. .)))
Most craters have been filled with water and have become lakes and others have fallen into the ocean.
(ROOT (S (NP (NNS Craters) (CC and) (NNS rifts)) (VP (VBP become) (NP (NNS lakes)) (SBAR (WHADVP (WRB when)) (S (NP (PRP they)) (VP (VBP fill) (PP (IN with) (NP (NN water))))))) (. .)))