Hamster<br>Sara's brothers was sad. His pet hamster died. Her brother was distant and just stood in his room all day. Sara's check came and Sara went to the pet store. She bought him a new hamster and he was happy.
Sara's brother is bipolar which is demonstrated at the ease in which she could reverse his disposition with a simple purchase. 
( z1 bipolar :domain ( z2 person :ARG0-of ( z3 have-rel-role :ARG1 ( z4 person :name ( z5 name :op "Sara" ) ) :ARG2 ( z6 brother ) ) ) :ARG0-of ( z7 demonstrate :ARG1 ( z8 easy :ARG1 ( z9 reverse :ARG0 z4 :ARG1 ( z10 disposition :poss z2 ) :instrument ( z11 purchase :ARG0 z4 :ARG1-of ( z12 simple ) ) :ARG1-of ( z13 possible ) ) ) ) )