题目内容：

    Elephants on the coast of Thailand are acting strangely. They stamp their feet and signal toward the hills. The sea draws back from the beaches. Fish fall heavily in the mud. Suddenly, a huge wave appears. This is no ordinary wave. It is a tsunami (海啸)!

Tsunami waves are larger and faster than normal surface waves. A tsunami wave can travel as fast as a jet plane and can be as tall as a ten-story building. Imagine dropping a stone into a pond. The water on the surface ripples (起涟漪). A tsunami is like a very powerful ripple. Tsunamis begin when the ocean rises or falls very suddenly. Large amounts of seawater are displaced. This movement causes huge waves.

If a tsunami happens, there must be some kind of force that causes the ocean water to become displaced. Most tsunamis are caused by underwater earthquakes. However, volcanoes, landslides (塌方), large icebergs, and even meteorites (陨石) are able to cause one of these giant waves.

Tsunamis are extremely powerful. Ordinary waves lose power when they break. Tsunami waves can remain powerful for several days. Because tsunami waves are so strong, they can kill people, damage property, and completely ruin an ecosystem in just one hour.

Scientists have no way of predicting when a tsunami will hit. However, if a powerful enough earthquake happens, scientists can send out a warning or a watch. A warning means that a tsunami will very likely hit soon. A watch means that conditions are favorable for a tsunami. When people are informed of a watch or a warning, they have more time to prepare. It is best not to get caught unaware when a tsunami is on the way!

1.Why are elephants acting strangely before the Tsunamis?

A.They dislike the huge wave.

B.They are afraid of the big fish.

C.They can sense something out of the ordinary.

D.They see the ocean drawing back from the beaches.

2.What does the underlined word “displaced” in paragraph 2 mean?

A.Moved out of normal place. B.Pushed by human force.

C.Pulled to great heights. D.Hung down quickly.

3.Why do Tsunamis cause so much destruction?

A.They are not familiar to most people.

B.They are very powerful and long-lasting.

C.They break on the coast, unlike normal waves.

D.They are caused by underwater earthquakes.

4.What is this text mainly about?

A.How to guard against tsunamis. B.Differences between wave types.

C.What to do with tsunami waves. D.Causes and effects of tsunamis.