Bob called to tell his mother that he couldn’t enter the house, for he ________ his key at school.
| A．had left | B．would leave |
| C．was leaving | D．has left |
“John took a photograph of you just now.” “Oh, really? I ______.”
| A．didn’t know | B．wasn’t knowing |
| C．don’t know | D．haven’t known |
When I arrived at the company, the manager ______, so we had only time for a few words.
| A．just went away | B．had gone away |
| C．was just going away | D．has just gone away |
The thief tried to break away from the policeman who ______ him, but failed.
| A．has held | B．had held |
| C．was holding | D．would hold |
The telephone _______ three times in the last hour, and each time it ________ for my father.
| A．had rang; was | B．has rung; was |
| C．rang; has been | D．has been ringing; is |
“Aha, you’re a chain smoker!” “Only at home. Nobody _______ that but you.”
| A．discovered | B．had discovered |
| C．discovers | D．is discovering |