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Elephants on the coast of Thailand are acting strange. They stamp their feet and motion toward the hills. The sea draws back from the beaches. Fish flop in the mud. Suddenly, a huge wave appears. This is no ordinary wave. It is a tsunami!
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. For a tsunami to occur, 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, large icebergs, and even meteorites are capable of causing one of these mighty waves. Tsunamis are extremely powerful. 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 occurs, scientists can issue a warning or a watch. A warning means that a tsunami will very likely hit soon. A watch means that conditions are favourable for a tsunami. When people are notified about 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!

28. Why are the elephants acting strange? *

A. They can sense something out of the ordinary.

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

C. They dislike wading into the ocean.

D. They are not used to seeing fish.

29. Which does not cause a tsunami? *

A. Meteorites

B. Volcanic eruptions

C. Earthquakes

D. Mudslides

30. Tsunamis cause so much destruction because they____ *

A. can be as tall as a ten-story building.

B. can be predicted by scientists.

C. are sometimes caused by volcanoes, landslides and meteorites.

D. break on the coast, unlike normal waves

31. What is this passage mostly about? *

A. Similarities and differences between wave types.

B. Scientists who predict tsunami waves.

C. How to prepare for tsunamis.

D. Causes and effects of tsunamis.

32. We can conclude from the last paragraph that _____ *

A. watch is more serious than warning.

B. watch and warning are equally serious.

C. warning is more serious than watch.

D. warning and watch both mean a tsunami has formed.