_____ the news, so far, has been good, there may be days ahead when it is bad.
| A．While | B．When | C．As | D．Since |
They kept trying _____ they must have known it was hopeless.
| A．if | B．because | C．when | D．where |
There are five pairs, but I'm at a loss which _____ to buy.
| A．to be chosen | B．to choose from | C．to choose | D．for choosing |
He was not an actor, who often appeared on stage, _____ a writer, writing stories.
| A．but | B．and | C．then | D．so |
Please make my excuse at tomorrow's meeting. I've got too much work _____.
| A．to do to come | B．doing coming | C．to do coming | D．doing to come |
I don't know whether to stay in teaching or _____ another job.
| A．trying getting | B．to try to get | C．trying to get | D．try get |