Before the final examination, many students have shown ____ of tension. Some have trouble in sleeping while others have lost their appetite.

It is very important for English teachers to have a knowledge of the theories of language_______. 

Provision of food and      is their main concern for the flood victims.

To our credit         , China overcame all the difficulties caused by the disasters in 2008 and successfully hosted the 29th Olympic Games.

We should bear in mind that social development and balance of nature should go  in         .