Great changes _____ in my hometown in the last 30 years and local people are living a happy life today.
| A．took place | B．were taken place |
| C．have taken place | D．have been taken place |
—Did you have any difficulty catching yesterday's lecture?
—No. The professor spoke very clearly to make his speech easy __________.
| A．understood |
| B．understand |
| C．understanding |
| D．to understand |
You should understand the traffic role by now. You've had it __________ often enough.
| A．explaining |
| B．to explain |
| C．explain |
| D．explained |
I couldn't do my homework with all that noise __________.
| A．going on |
| B．goes on |
| C．went on |
| D．to go on |
With the financial crisis __________ across the globe, a lot of companies have shut down and many people have been out of work.
| A．spread |
| B．spreading |
| C．to spread |
| D．having spread |
Students should have their homework __________ by themselves not by copying others'.
| A．finished |
| B．finishing |
| C．to finish |
| D．finish |