Every possible means __to prevent the air pollution, but the sky is still not clear.
| A．are being used | B．have been used |
| C．has been used | D．had been used |
A simple 45-minute operation __________ by scientists is hoped to cure blindness in six years.
| A．being developed |
| B．developed |
| C．to develop |
| D．developing |
__________ in a well-known university is what every-body wishes for.
| A．Educated |
| B．To educate |
| C．Educating |
| D．Being educated |
Taking physical exercise regularly is an effective way to avoid __________ with the flu.
| A．to infect |
| B．infecting |
| C．to be infected |
| D．being infected |
—Is there any possibility of the film __________ in Paris International Festival?
—Not in the least, because the audience generally think little of it.
【选项 】
| A．trying out |
| B．tried out |
| C．to try out |
| D．being tried out |
__________ three times in a row, the boxer decided to give up fighting.
| A．Having defeated |
| B．To have defeated |
| C．Having been defeated |
| D．To have been defeated |