The rivers will become dirtier and dirtier ______ we take action to protect them.
| A．since | B．if | C．until | D．unless |
—Who is in the classroom besides Li Lin？
—________．
| A．Nobody else |
| B．Nobody other |
| C．Else nobody |
| D．Other nobody |
—Have they________Beijing yet？
—Yes，they have________．
| A．arrived；arrived |
| B．arrived in；arrived |
| C．reached in；got |
| D．reached；arrived in |
—________you________Beijing before？
—Yes．I________Beijing last year．
| A．Did；visit；visited |
| B．Have；visited；went to |
| C．Have；visited；have visited |
| D．Do；visit；have visited |
Have you decided which book________about for English class？
| A．writing |
| B．to writing |
| C．write |
| D．to write |
—Have you finished your homework________？
—Yes，I have________finished it．
| A．yet；yet |
| B．already；already |
| C．yet；already |
| D．already；yet |