Not until ________a third time ________that he had given birth to the reading system for the blind called Braille.
| A．Louis Braille tried；he announced |
| B．did Louis Braille try；he announced |
| C．Louis Braille had tried；did he announce |
| D．had Louis Braille tried；had he announced |
Sarah looked at ______finished painting with ________satisfaction.
| A．/；a | B．a；the | C．the；/ | D．the；a |
Special attention should be paid ________our earth from________.
| A．to prevent；being polluted |
| B．to prevent；polluting |
| C．to preventing；being polluted |
| D．to preventing；polluted |
Most students at school hope that they can ________activities that appeal to them after class instead of just doing their homework.
| A．apply for | B．participate in |
| C．stick to | D．focus on |
It is said that the café being built near the post office ________mainly to the workers from the factory across the road.
| A．caters | B．serves | C．contributes | D．supplies |
________of stealing money from the bank，he was being questioned by the police.
| A．Accusing | B．Accused |
| C．Having accused | D．To accuse |