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

A terrible earthquake broke out in Chile in February, _______ hundreds of people.

       form the moon, our earth with water        .seventy percent of its surface, appears as a blue ball.

Today the number of people ________ English in China is increasing rapidly.

When ____ to danger and conflict, men tend to increase blood pressure, ______ nervous and  anxious.