2 . 选用方框内合适的内容替换下列句子中的划线单词。

A. at once                         B. broke out             C. happen D. official statement             E. terrible storm

1. The writer was sleeping downstairs when the volcano erupted.
2. When the fire alarm sounds, act immediately to ensure your safety.
3. We were shocked by the announcement that the heavy rain caused a landslide.
4. If headaches only occur at night, lack of fresh air and oxygen is often the cause.
5. A hurricane can tear down houses, cause landslides and floods and leave millions homeless.

4 . 根据语境及汉语提示写出正确的单词
1. natural ________ (灾难)
2. glass ________ (管子)
3. volcanoes ________ (爆发)
4. reply ________ (立刻, 马上)
5. ________ (飓风)lamp
6. ________ (滑坡) control
7. never ________ (发生)
8. official ________ (通知)