--- Have you known Dr Jackson for a long time?
--- Yes, since she the Chinese Society.
| A．has joined |
| B．joins |
| C．had joined |
| D．joined |
______ environmental damage is done，it takes many years for the ecosystem to recover．
| A．Even if | B．If only |
| C．As if | D．Once |
If Susan ______ for ten more minutes at the party last night, she might have met Johnny Depp, the famous Hollywood star．
| A．stayed | B．would stay |
| C．had stayed | D．would have stayed |
Passers-by rescued a motorcycle driver ______ under a burning car．
| A．was trapped | B．trapping |
| C．having trapped | D．trapped |
More people are choosing to work ______ retirement age．
| A．at | B．in |
| C．for | D．beyond |
—Where would you like to sit? In the corner or near the platform?
—______．I would like to sit by the piano so that I can watch the musician play．
| A．Either | B．Neither |
| C．None | D．Both |