One third of the class _____ agreed to be volunteers to help the aged this vocation.
| A．are | B．is | C．has | D．have |
The text is too difficult. The explanation of our teacher will help make it easy ________.
| A．to understand | B．to be understood |
| C．understood | D．understanding |
It is said that sixty percent of all energy ________ in the world today is being lost as waste heat.
| A．produced | B．producing |
| C．to produce | D．having produced |
________ clearly ________ nothing to do, the soldiers left the village the next day.
| A．It; was | B．It; being |
| C．There; was | D．There; being |
—I regret ________ you that your application has not been successful.
—Not successful? I performed pretty well in my interview!
| A．informing | B．to inform |
| C．having informed | D．to have informed |
As is known to all, one of the many benefits of ________ adventure travel is teaching children how to cope with ________ unexpected.
| A．the; / | B．/; an | C．the; the | D．/; the |