_____the program, they have to stay there for another two weeks.
| A．Not completing | B．Not having completed |
| C．Not completed | D．Having not completed |
28. If our car had not ________, we would have been here on time.
| A．broken out | B．broken into | C．broken away | D．broken down |
27. This new kind of chemicals will help keep the air, soil and water________ from pollution.
| A．free | B．empty | C．loose | D．Short |
26. Barack Obama has taken personal blame ________ the security failures which led ________ the attempt to blow up a plane on Christmas Day.
| A．of; to | B．for; to | C．on; on | D．in; on |
24. My father didn’t have to say anything. I knew he was upset from his ________.
| A．look | B．sight | C．appearance | D．Sign |
23. Cao Cao’s tomb is reported ________ in China, which attracts nationwide attention.
| A．being found | B．to be found |
| C．having been found | D．to have been found |