---What were you doing when Tom came to see you?
---I had just put on my overcoat and_____ to visit my friends.
| A．left | B．was left | C．was leaving | D．had left |
As ______along the river bank, she was singing a pop song.
| A．walking | B．walked | C．to walk | D．walk |
_____ is known to everybody, Taiwan is part of China. We must unify it.
| A．It | B．As | C．That | D．What |
---I rang you yesterday afternoon. A man answered, but I didn’t recognize the voice.
--- Oh, it ____ my uncle. He was in my room then.
| A．must have been | B．should have been | C．must be | D．should be |
Mrs.Black took the police back to ____ place ____ she witnessed the robbery.
| A．the same, that | B．the same, as |
| C．the same, where | D．as the same, as |