In order to finish the experiment successfully, the professor always _________, for every day the light in his room didn’t go out until 4 a.m.
| A．mixed up | B．cleaned up | C．turned up | D．stayed up |
The cause he had devoted himself to __________a perfect success.
| A．proving | B．proved | C．was proved | D．has been proved |
— Have you handed in your papers?
—Yes, we have. I guess they ___________ now.
| A．have corrected | B．are corrected | C．are being corrected | D．are correcting |
The company _______ a rise in salary for ages but nothing has happened yet.
| A．has been promising | B．had promised | C．promised | D．promises |
—Why does the river smell terrible?
—Because large quantities of water__________．
| A．have polluted | B．is being polluted | C．has been polluted | D．have been polluted |
Months ago we sailed ten thousand miles across the open sea, which_____ the Pacific,and we met no storm.
| A．was called | B．is called | C．had been called | D．has been called |