问题
选择题
My pain ___________ obvious the moment I walked into the room, for the first
man I met asked me pitifully:" Are you feeling all right?"
A．must be
B．must have been
C．could be
D．could have been
答案
答案：B
本题是情态动词的考查。根据后半个分句可以知道谓语动词发生于过去，而情态动词+动词的完成式表示对过去的推测。