If I had worked harder at school, I ___ in a comfortable office now.
| A．would have sat | B．had sat | C．would be sitting | D．could sit |
------Is there anything wrong , Bob? You look sad.
------ Oh, nothing much. In fact, I ______ of my friends back home.
| A．have just thought | B．was just thinking |
| C．would just think | D．will just be thinking |
The country has already sent up three unmanned spacecraft, the most recent ______ at the end of last March..
| A．has been launched | B．having been launched |
| C．being launched | D．to be launched |
------Where did you get to know her?
------ It was on the farm ______ we worked.
| A．there | B．that | C．where | D．there |
______ I really don’t like art, I find his work impressive.
| A．As | B．Since | C．If | D．while |
______ worries me the way he keeps changing his mind.
| A．This | B．That | C．What | D．It |