On that occasion, Lisa had seen a ferocious dog barking behind the chain-linked fence.
( ( On ( that occasion ) ) ( , ( Lisa ( ( had ( seen ( ( a ( ferocious dog ) ) ( barking ( behind ( the ( chain-linked fence ) ) ) ) ) ) ) . ) ) ) )
(ROOT (S (PP (IN On) (NP (DT that) (NN occasion))) (, ,) (NP (NNP Lisa)) (VP (VBD had) (VP (VBN seen) (NP (NP (DT a) (JJ ferocious) (NN dog)) (VP (VBG barking) (PP (IN behind) (NP (DT the) (JJ chain-linked) (NN fence))))))) (. .)))
At that particular time, Lisa had seen a fierce dog behind a fence. 
( ( At ( that ( particular time ) ) ) ( , ( Lisa ( ( had ( ( seen ( a ( fierce dog ) ) ) ( behind ( a fence ) ) ) ) . ) ) ) )
(ROOT (S (PP (IN At) (NP (DT that) (JJ particular) (NN time))) (, ,) (NP (NNP Lisa)) (VP (VBD had) (VP (VBN seen) (NP (DT a) (JJ fierce) (NN dog)) (PP (IN behind) (NP (DT a) (NN fence))))) (. .)))