-----Did Mary come to the party?
---I don’t know．She _____while I was out．
A．may have come B．must have come
C．might come D．could come
The old man leads ______happy life now, but he will never forget ______hard time when he was poor.
A.the, a B. /; the C. the; / D. a, the
---I regret _____you John has been fired．
---I can hardly believe my ears．He’s such a fine worker．
A．telling B．having told C．to tell D．to have told
---Alice, you look puzzled, Have you understood it?
---No．I _____another problem just now．
A．l have thought of B．am thinking of
C．had thought of D.was thinking of
How pleased the detective was _____what his customer told him!
A．hearing B．to hear C．heard D．to hearing
She looks forward every spring to _____the flower-lined garden．
A．walking in B．walk in C．visit D．paying a visit
