If only I ________ driving before.
| A．learn | B．learned | C．had learned | D．would learn |
— I phoned you yesterday morning. A girl answered, but I didn’t recognize the voice.
— Oh, it ____ my younger sister. She was in my room at that moment.
| A．must have been | B．should have been | C．could have been | D．may have been |
The old woman who______in the deserted house alone for ten years has been settled in a nursing home now.
| A．lived | B．has lived | C．had lived | D．has been living |
The new buyer identified a dozen new sources for the material, ___________ proved to be reliable．
| A．most of them | B．most of which | C．most of whom | D．most of those |
_____ I say Clancy is a smart boy, he still needs to work hard to achieve his goal.
| A．Then | B．When | C．While | D．As |
Unfortunately, ____ stone hit him on ______ head and he got injured.
| A．the; a | B．a; 不填 | C．a; the | D．the; the |