fix

ps-grammar/rsm/rsm.jsgf

 #JSGF V1.0;
 grammar A4_rsm;
-public <rsm> = [the] <furniture> [is] [on] [the] [in] ( <IN_FRONT_OF> | <BEHIND> | <RIGHT_OF> | <LEFT_OF> ) [of] [the] <furniture>;
+public <rsm> = [the] <furniture> is ( <IN_FRONT_OF> | <BEHIND> | <RIGHT_OF> | <LEFT_OF> ) of the <furniture>;
 
 <furniture> = ( ( sofa | couch ) | chair | cupboard | shelf | table ) ;
 <IN_FRONT_OF> = ( before | front );