________back at my middle school years，I regret not having worked so hard as I should have.
| A．Looking |
| B．To look |
| C．Looked |
| D．Look |
They are broadening the bridge to ___ the flow of traffic.
| A．put off |
| B．speed up |
| C．turn on |
| D．work out |
Film has a much shorter history, especially when ___ such art forms as music and painting.
| A．having compared to |
| B．comparing to |
| C．compare to |
| D．compared to |
Time, __ correctly, is money in the bank.
| A．to use |
| B．used |
| C．using |
| D．use |
___ by the advances in technology,many farmers have set up wind farms on their land.
| A．Being encouraged |
| B．Encouraging |
| C．Encouraged |
| D．Having encouraged |
___ many times, he finally understood it.
| A．Told |
| B．Telling |
| C．Having told |
| D．Having been told |