—Believe it or not, I have met him before.
—No kidding? ________ you've never mentioned it?
| A．What for | B．How come |
| C．How about | D．What if |
If you find yourself ______ no one will help you, please call me.
| A．which | B．when |
| C．where | D．what |
The government has taken some measures to solve the shortage of water, but it may be some time __ the situation improves.
| A．since | B．when. |
| C．unless. | D．before. |
— Why was it so noisy over there?
— The Twins were surrounded by their fans ____ they stepped out of the hall.
| A．until | B．the moment |
| C．in case | D．so that |
Among the many dangers_________-- sailors have to face, probably the greatest of all is fog.
| A．which | B．what |
| C．where | D．when |
Mr. Black is willing to do ____________ Mrs．Black tells him to do．
| A．whichever | B．however |
| C．whatever | D．whenever |