Thegreathallwascrowdedwithmanypeople,___manychildren____ontheirparents'lapsa.including,seatedb.including,seatingc.included,satd.included,sitting为什么我选了d,为什么不可以,是不是只要有seat,就一定用过去式?

　　Thegreathallwascrowdedwithmanypeople,___manychildren____ontheirparents'laps

　　a.including,seated

　　b.including,seating

　　c.included,sat

　　d.included,sitting

　　为什么

　　我选了d,为什么不可以,是不是只要有seat,就一定用过去式?