And Doctor Perennial just stood there and when the evil drill sergeant woke up in him once again, he received an SMs.  
( And ( ( ( ( ( Doctor Perennial ) ( just ( stood there ) ) ) and ) ( ( when ( ( the ( evil ( drill sergeant ) ) ) ( ( woke ( up ( in him ) ) ) ( once again ) ) ) ) ( , ( he ( received ( an SMs ) ) ) ) ) ) . ) )
(ROOT (S (CC And) (S (NP (NNP Doctor) (NNP Perennial)) (ADVP (RB just)) (VP (VBD stood) (ADVP (RB there)))) (CC and) (S (SBAR (WHADVP (WRB when)) (S (NP (DT the) (JJ evil) (NN drill) (NN sergeant)) (VP (VBD woke) (ADVP (RB up) (PP (IN in) (NP (PRP him)))) (ADVP (RB once) (RB again))))) (, ,) (NP (PRP he)) (VP (VBD received) (NP (DT an) (NN SMs)))) (. .)))
Doctor Perennial was sitting down when the evil drill sergeant walked up to him and delivered a letter. 
( ( Doctor Perennial ) ( ( was ( ( sitting down ) ( when ( ( the ( evil ( drill sergeant ) ) ) ( ( ( ( walked up ) ( to him ) ) and ) ( delivered ( a letter ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Doctor) (NNP Perennial)) (VP (VBD was) (VP (VBG sitting) (PRT (RP down)) (SBAR (WHADVP (WRB when)) (S (NP (DT the) (JJ evil) (NN drill) (NN sergeant)) (VP (VP (VBD walked) (PRT (RP up)) (PP (TO to) (NP (PRP him)))) (CC and) (VP (VBD delivered) (NP (DT a) (NN letter)))))))) (. .)))