Reba gets robbed<br>Reba is walking down the street. She gets mugged. Her purse is taken and her watch. She tries running after them. She cannot catch them and they get away.
Reba was robbed by multiple people. 
The passage states that Reba was robbed by "them," meaning that she was robbed by more than one person. 
( z1 rob :ARG0 ( z2 person :quant ( z3 multiple ) ) :ARG1 ( z4 person :name ( z5 name :op "Reba" ) ) )