Then I have learned there are a lot of troubles in our lives, but the problem is __________ they control you or you control them.

Please call my secretary to arrange a meeting this afternoon，or________it is convenient to you.                                                            

Helen plays the piano well, ____her favourite instrument is the violin.

（2014年安徽省合肥市高三第三次教学质量检测）31. What the whole nation cares about most at present is ______ the rescue teams could find the missing plane.

We can’t help you ____ you tell us what’s wrong.