问题补充:
单选题“Nothavingreturnedhomeyet,_________”,hisfathersaidtothepolice.A.his mother got worriedB.his mother must be worriedC.I think he is missingD.he must have got into some trouble.
答案:
D解析句意: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。