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

— What should I do before operating the new machine?— You’d better read its ______ first carefully.

There is reason to believe that most writers have difficulty in ______ the opening paragraphs of their papers.

Fengjun，_______ president of Aigo Technology Company, is the second Chinese billionaire to promise        _________all-donation after Chen Guangbiao.

Many countries are increasing their use of natural gas, wind and other forms of ____.