答案　A

解析　主旨大意题。通读全文可以看出，这篇文章主要讲述的是黑暗的海底世界的一些情况。

2．The world's longest mountain range under the ocean .

A．extends 1,600 kilometers under the Atlantic Ocean

B．is called the Mid­Atlantic Ridge

C．contains few high peaks

D．extends from Iceland to the Azores

答案　B

解析　细节理解题。由第二段可得出本题的答案。

3．From this passage we know that .

A．the longest and the highest mountains lie in the sea

B．the highest mountain lies on land

C．the longest mountain lies on land

D．Mauna Kea is 4,221 meters high

答案　A

解析　细节理解题。由第二、三段我们知道，最长的山脉在大西洋，最高的山峰则在太平洋中部的夏威夷。据此，我们可得出本题的答案。

4．If a kind of creature lives in an sea area about 300 meters from the surface， .

A．the creature won't have enough food to eat

B．the creature will feel very cold

C．the creature will have to give light by itself

D．the creature will feel too hot

答案　C

解析　推理判断题。从最后一段我们知道，阳光只能到达离海面244米的地方，在此以下的地方生活的动物就必须靠自己的发光系统照明。

As a seal rests on ice floating on the Antarctic Ocean，it should feel safe.But it is about to become a victim of a group of killer whales who have developed a great skill to catch seals.The killer whales work together as a group to create large waves that wash seals off the ice.

Scientists who have discovered the technique，which has only been seen in killer whales hunting