They did not sell a single car for a month and had to ________ some workers.
| A．lay out | B．lay up |
| C．lay off | D．lay down |
Though we don't know what was discussed, yet we can feel the topic __________.
| A．had changed | B．will change |
| C．was changed | D．has been changed |
—What is the price of petrol these days?
—Oh, it __________ sharply since last month.
| A．is raised | B．has risen |
| C．has arisen | D．is increased |
—Why does the lake smell terrible?
—Because large quantities of water __________.
| A．have polluted | B．is being polluted |
| C．has been polluted | D．have been polluted |
Progress __________ so far very good and we are sure that the work will be finished on time.
| A．was | B．had been |
| C．has been | D．will be |
For many years, people __________ electric cars. However, making them has been more difficult than predicted.
| A．had dreamed of | B．have dreamed of |
| C．dreamed of | D．dream of |