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 |
Since the time humankind started gardening, we _____to make our environment more beautiful.
| A．try | B．have been trying |
| C．are trying | D．will try |
We won’t start the work until all the preparations __________.
| A．are being made | B．will be made |
| C．have been made | D．had been made |
Sofia looked around at all the faces: she had the impression that she _____ most of the guests before.
| A．has seen | B．had seen |
| C．saw | D．would see |
James has just arrived, but I didn’t know he _______ until yesterday.
| A．will come | B．was coming |
| C．had come | D．came |
During his stay in Xi’an, Jerry tried almost all the local foods his friends ________,
| A．would recommend |
| B．had recommended |
| C．have recommended |
| D．were recommending |