Located between the continents of North America,South America,Antarctica and Oceania,the Pacific Ocean is the largest of the world’s four oceans.It covers about one-third of the surface of the earth,more surface area than all the continents combined.It is commonly divided at the equator(赤道)into the North Pacific and the South Pacific.The southern part has thousands of small volcanic islands.To the north lie the Aleutian Islands, another line of volcanoes, and the Bering Sea.The eastern coast is marked by the Americas.
The tallest mountain in the world is found in the Pacific Ocean:Mauna Kea of the Hawaiian Islands.From the base of the volcano on the ocean floor it is 33,476feet.That is 4,441feet higher than Mount Everest.The deepest trench(海沟)in the world is also in the waters of the Pacific Ocean.At 36,198feet deep, the Mariana Trench would cover Mount Everest with 1.4miles of water above to spare.
All the volcanic regions on the western,northern and eastern edges are known as the Ring of Fire.These areas of volcanic activity are caused by the movement of plates.In addition to the threat of volcanic eruption,earthquakes are a common occurrence along the Ring of Fire.Many of the earthquakes are among the strongest in the world.
With the threat of earthquakes comes the threat of tsunamis(海啸).These giant waves can travel at a speed of up to 500miles per hour, appearing just as small waves in the deep sea.Often these waves go undetected by ships they pass beneath.
From the first paragraph we learn that the Pacific Ocean ___.

A．covers about half of the surface of the earth

B．is commonly divided into four parts

C．contains the Aleutian Islands and the Bering Sea

D．is surrounded by five continents

Which of the following statements about Mauna Kea is TURE according to the passage?

A．The part above the water is 33,476 feet

B．It is a part of the Hawaiian Islands

C．It isn’t a volcano

D．It is as high as Mount Everest

If we put Mount Everest into the Mariana Trrench,we would ___.

A．see only the top of it

B．not see any part of it

C．see about half of it

D．see only one-third of it