This afternoon Mr Smith will give us a report on nuclear energy , which is well worth _____.

 We all think it most foolish ______ this mistake.

           in thought, he sat at the edge of the bed, with his eyes           on the letter in his hand.

Under the environment of fierce competition, the only way John could imagine____stress was to get tougher by making greater efforts.

In the recent coal mine accident, more than one hundred miners were left ______underground.