When Mr. Hastings and Mr. Lawrence came in yesterday evening, they found your mistress busy writing letters. 
( ( When ( ( Mr. ( Hastings ( and ( Mr. Lawrence ) ) ) ) ( ( came ( in yesterday ) ) evening ) ) ) ( , ( they ( ( found ( ( your mistress ) ( busy ( writing letters ) ) ) ) . ) ) ) )
(ROOT (S (SBAR (WHADVP (WRB When)) (S (NP (NNP Mr.) (NNP Hastings) (CC and) (NNP Mr.) (NNP Lawrence)) (VP (VBD came) (PP (IN in) (NP (RB yesterday))) (NP (NN evening))))) (, ,) (NP (PRP they)) (VP (VBD found) (S (NP (PRP$ your) (NN mistress)) (ADJP (JJ busy)) (S (VP (VBG writing) (NP (NNS letters)))))) (. .)))
Last night no one saw your mistress.
( ( Last night ) ( ( no one ) ( ( saw ( your mistress ) ) . ) ) )
(ROOT (S (NP (JJ Last) (NN night)) (NP (DT no) (NN one)) (VP (VBD saw) (NP (PRP$ your) (NN mistress))) (. .)))