Do you know where your father is?I think he______on the computer

问题描述:

Do you know where your father is?I think he______on the computer
A.must chatB.must be chattedC.could chatD.could be chatting

答案选 :D.麻烦告诉下理由mush be是肯定猜测,could be是否定猜测。而且是对现在的事实进行推测,所以选d