“Nothavingreturnedhomeyet,_________”,

hisfathersaidtothepolice.

A.his mother got worriedB.his mother must be worriedC.I think he is missingD.he must have got into some trouble.在线课程D
句意：他的父亲对警察说：“还没回到家呢，他一定陷入了困境当中。must have done表示对过去事情肯定的推测。所以选D。