Jade is the highest award in Chinese culture and medals are the most important prize in Olympics，so medals with jade is the perfect ______ to present the Olympics in Beijing.

It can’t be a（n） _______ that four jewelry stores were robbed in one night．

 All the members of the WTO should follow the ______ of trust and fair(公平) trade.

I have to reschedule the appointment with you since there is a ______ in my arrangement. 

If you don’t speak good English,you will be at a big      when you try to get a good job.