The young couple, who returned my lost wallet, left ______I could ask for their names．
| A．while | B．before | C．after | D．since |
－Oh, it’s you, Steve! I ________ you.
－No surprising. I’ve just had my hair cut.
| A．don’t recognize | B．haven’t recognized | C．didn’t recognize | D．hadn’t recognized |
I would have come sooner but I ________ that they were waiting.
| A．haven’t known | B．hadn’t known | C．don’t know | D．didn’t know |
—Did you find the missing couple in the mountain yesterday?
—No, but we ________ to get in touch with them ever since.
| A．have tried | B．have been trying | C．had tried | D．had been trying |
—Such a mistake could have been avoided.
—Unfortunately, he ________ the mistake again and again.
| A．repeated | B．would repeat | C．had repeated | D．would have repeated |
The student didn’t pay any attention to the lecture; he ________ of something else.
| A．thought | B．had thought | C．would think | D．was thinking |