He had to sell his luxury car, ________ his company was in debt.
| A．before | B．until |
| C．while | D．for |
Neither Tom nor his parents ______ at home.
| A．is | B．are | C．has | D．was |
The only means to achieve success ___ to appeal to arms.
| A．is | B．are | C．were | D．have |
One or perhaps more pages _______.
| A．is missing | B．has been missed | C．are missing | D．was missing |
The Smiths ______ their breakfast when the doorbell rang.
| A．had | B．has been having | C．are having | D．were having |
The majority of doctors ______ smoking is harmful to health.
| A．are believed | B．had believed | C．has believed | D．believe |