阅读下面材料，在空白处填入适当的内容(1个单词或括号内的单词的正确形式)。
    Earthquakes are quite common. In fact, thousands of earthquakes happen each day. Most of them are weak to feel, though. During a big earthquake, there is often a big noise first. Then the earth shakes (terrible) and many houses fall down.
     As one of the most deadly natural  （disaster) in the world, earthquakes often result in many people being injured or killed. In 2008, a severe earthquake hit China's Sichuan Province, which(kill) more than 80,000 people there.  
    Besides, the great damage and deaths caused by the earthquake(it), other accidents such as fires often follow. (much) buildings may be damaged and more deaths may be caused.
    For centuries, man have been making studies of earthquakes. About 2,000 years ago, for example, a Chinese scientist named Zhang Heng invented a machine, which could find out from which direction the earthquake waves came. With the rapid (develop) of modern science and technology, we now know a lot more about earthquakes. However, scientists still have
difficulty  (predict) exactly when and where earthquake will happen, and can't stop it happening.