Such a fierce dog __ that we had to wait outside before we could get into his yard．
| A．has he had | B．did he have |
| C．he had | D．he has had |
—Oh, my God! My English book is nowhere to be seen.
—You __________ it at home.
| A．should have left | B．would have left |
| C．must have left | D．could have left |
To their relief, the doctor told them that if proper _______, Betty could recover very soon.
| A．treating | B．treated |
| C．being treated | D．to be treated |
_______ there are many different types of food, some animals spend their lives eating only one type.
| A．Since | B．Unless |
| C．Once | D．While |
As the Internet has gained popularity, there has been a change in the way ______ people spend their time.
| A．which | B．in which |
| C．where | D．when |
—Which city is the first ________ plastic shopping bags?
—As far as I know, it is San Francisco.
| A．banned | B．ban |
| C．banning | D．to ban |