each boy and each girl--- to help.A asks B is asked

each boy and each girl___ to help.A asks B is asked答案给的是A.但ask 是及物动词,何来 ask to do 本人认为是B答案.意欲考证下,望高手不吝赐教.Many thanks!PS：认为主语each boy and each girl是复数的,请嘴下留情,麻烦多多看书.