---Hurry, John!
---Oh, damn! Both my legs are nearly to give out. I ____for hours.
| A．had walked | B．walked | C．have been walking | D．am walking |
We will debate the subject_____ late when we have enough time.
| A．in vain | B．at length | C．at last | D．in force |
We will debate the subject_____ late when we have enough time.
| A．in vain | B．at length | C．at last | D．in force |
We will debate the subject_____ late when we have enough time.
| A．in vain | B．at length | C．at last | D．in force |
While watching television, __________.
| A．the doorbell rang | B．the doorbell rings |
| C．we heard the doorbell ring | D．we heard the doorbell rings |
John, look at the time. ___________ you play the piano at such a late hour?
| A．Must | B．Can | C．May | D．Need |