When a big ship is in very rough(不平坦的) sea, it has to be able to bend(弯) a little, otherwise it may break in two. If one end of the ship is on the top of one huge wave, and the other end is on the top of another, with the middle of the ship hanging in between; or if one huge wave comes up under the middle of the ship, leaving the two ends hanging, the ship's own weight will break its back if it is quite stiff(硬的).

　　To make a big ship elastic(有弹性的) enough to avoid (避开) this danger, it has joints where the sections of the ship come together above the water-line, and these joints (连接处) open and shut slightly as the waves lift one section(部分) of the ship or another. This is enough to save the ship from breaking into pieces.

　　One day a sailor was walking along a passage-way in a big ship during a storm when he was surprised to see a boy sitting comfortably in a chair at the end of the passage-way, which was opposite one of the ship's joints. The boy had a bag of nuts beside him, and every time the ship was lifted by a wave and the joint opened, he put a nut in it. As the ship came down again, the joint closed and cracked(压碎) the nut, gently but firmly. The boy then took it out and put the next one in as the joint opened again.

1．What does a big ship have to do when it is in very rough sea?

2．If one end of the ship is on the top of one huge wave, and the other end is on the top of another, with the middle of the ship hanging in between, what will happen to the ship if it is quite stiff?

3．Why does a big ship have joints?

4．What do these joints do?

5．Where was a sailor walking during the storm in this story?

6．What was he surprised to see?

7．What did the boy have beside him?

8．What did he do?

9．How was the nut cracked?

10．What did the boy do then?

As we all know, the ocean moves. But waves breaking on the beach make the ocean fun. When you stand on the shore and look at the waves, it seems like the water is moving towards you. But the water is not really moving forward. The moving you see is wave energy. And wave energy comes from the wind.
Let’s think about how this works. As wave energy passes through the water, the energy makes particles （粒子） of water move up and down. Just give you an example of a wave passing under a basketball. We put a basketball on the sea. When the wind blows, a wave comes from behind the basketball. The basketball moves up to the top with the wave. Then the wave continues and leaves the basketball behind. The basketball looks lower, but it doesn’t move forward. That’s because the wave energy just moves the water which is under the basketball.
　  So why can you see a wave knock you down on the shore？When a wave moves toward the shore, the bottom of the wave slows down because it meets the ocean floor. But the top, which is called crest(浪峰), keeps moving. The different action causes the wave to fall over or break onto the shore. If a wave is very large, it carries a lot of energy when it hits the land. As time goes by, waves can break up and carry away the rocks and other things on the shore. Shorelines are changing all the time because of wave action.
【小题1】______ is really moving forward when you look at the wave.

As we all know, the ocean moves. But waves breaking on the beach make the ocean fun. When you stand on the shore and look at the waves, it seems like the water is moving towards you. But the water is not really moving forward. The moving you see is wave energy. And wave energy comes from the wind.

Let’s think about how this works. As wave energy passes through the water, the energy makes particles （粒子） of water move up and down. Just give you an example of a wave passing under a basketball. We put a basketball on the sea. When the wind blows, a wave comes from behind the basketball. The basketball moves up to the top with the wave. Then the wave continues and leaves the basketball behind. The basketball looks lower, but it doesn’t move forward. That’s because the wave energy just moves the water which is under the basketball.

　  So why can you see a wave knock you down on the shore？When a wave moves toward the shore, the bottom of the wave slows down because it meets the ocean floor. But the top, which is called crest(浪峰), keeps moving. The different action causes the wave to fall over or break onto the shore. If a wave is very large, it carries a lot of energy when it hits the land. As time goes by, waves can break up and carry away the rocks and other things on the shore. Shorelines are changing all the time because of wave action.

1.______ is really moving forward when you look at the wave.

A．Water            B．The basketball      C．Water and wave energy   D．Wave energy

2.Match the sentences with the pictures and the right answer.

(1) The basketball moves up to the top with the wave.

(2) The basketball continues and leaves the basketball behind.

(3) When the wind blows, a wave comes from behind the basketball.

A．a—(2) b—(1) c—(3)                     B．a—(3) b—(1) c—(2)

C．a—(1) b—(3) c—(2)                     D．a—(3) b—(2) c—(1)

3.Which of the following is NOT true according to the passage?

A．Wave energy comes from the water.

B．Large waves carry plenty of energy.

C．Wave action makes shorelines change all the time.

D．The bottom of the wave is easy to slow down.

4.The underlined word “it” ( Paragraph 3) refers to “________”.

A．particles of water   B．the shore          C．the wind          D．the bottom of the wave

5.The main idea of this passage is ______.

A．what makes particles of water move         B．how a basketball moves on the ocean

C．how wave energy causes wave action        D．why a wave can knock you down