The little boy is dirty from head to foot because he______in the mud all morning.

A．has played 　

B．is playing

C．has been playing

D．was playing

下列除哪项外均表现为瞳孔缩小（）

A.有机磷农药中毒

B.吗啡类药物中毒

C.毒蕈碱中毒

D.巴比妥类中毒

E.酒精中毒