Another unit was added on to the communal dwelling each time a marriage created a new family.
( ( ( Another unit ) ( was ( ( added ( on ( to ( the ( communal dwelling ) ) ) ) ) ( each time ) ) ) ) ( ( a marriage ) ( ( created ( a ( new family ) ) ) . ) ) )
(ROOT (S (S (NP (DT Another) (NN unit)) (VP (VBD was) (VP (VBN added) (PP (IN on) (PP (TO to) (NP (DT the) (JJ communal) (NN dwelling)))) (NP (DT each) (NN time))))) (NP (DT a) (NN marriage)) (VP (VBD created) (NP (DT a) (JJ new) (NN family))) (. .)))
A new unit is put on the communal dwelling every instance a new family was created through marriage.
( ( A ( new unit ) ) ( ( is ( ( put ( on ( the ( communal dwelling ) ) ) ) ( ( every instance ) ( ( a ( new family ) ) ( was ( created ( through marriage ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT A) (JJ new) (NN unit)) (VP (VBZ is) (VP (VBN put) (PP (IN on) (NP (DT the) (JJ communal) (NN dwelling))) (NP (NP (DT every) (NN instance)) (SBAR (S (NP (DT a) (JJ new) (NN family)) (VP (VBD was) (VP (VBN created) (PP (IN through) (NP (NN marriage)))))))))) (. .)))