I was to watch for an advertisement in the Times.
( I ( ( was ( to ( watch ( for ( ( an advertisement ) ( in ( the Times ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (PRP I)) (VP (VBD was) (S (VP (TO to) (VP (VB watch) (PP (IN for) (NP (NP (DT an) (NN advertisement)) (PP (IN in) (NP (DT the) (NNP Times))))))))) (. .)))
I looked for an ad in my mailbox. 
( I ( ( ( looked ( for ( an ad ) ) ) ( in ( my mailbox ) ) ) . ) )
(ROOT (S (NP (PRP I)) (VP (VBD looked) (PP (IN for) (NP (DT an) (NN ad))) (PP (IN in) (NP (PRP$ my) (NN mailbox)))) (. .)))