At times the balance in nature is ______ , resulting in a number of possibly unforeseen effects.
| A．troubled | B．confused | C．disturbed | D．puzzled |
He hesitated for a moment before kicking the ball, otherwise he __________ a goal.
| A．had scored | B．scored | C．would score | D．would have scored |
If I hadn't been lucky enough to meet you, I really __________ what I would have done.
| A．don't know | B．hadn't known |
| C．wasn't knowing | D．wouldn't know |
The company __________ a rise in salary for years, but nothing has happened.
| A．promises | B．promised |
| C．has promised | D．has been promising |
I'm glad to see that you __________ a lot of progress since I__________ you last.
| A．will make; have met | B．have been making; met |
| C．had made; met | D．have made; meeting |
—Did you find the missing couple in the mountain yesterday?
—No, but we __________ to get in touch with them ever since.
| A．have tried | B．have been trying | C．had tried | D．had been trying |