(C)
The ocean is really important for the earth. There are one million kinds of animals living in the oceans. It covers over 70% of the earth. It keeps the weather stable (稳定的) and produces 70% of the oxygen for humans. For a long time, we have travelled on the oceans and they give us food. But there are still lots of things waiting for us to find out.
Four or five basins (盆地)
The earth has four ocean basins: the Pacific, Indian, Atlantic and Arctic Oceans. Most countries now think the Southern is the fifth ocean basin. The Pacific is the largest, covering 30% of the earth. At its widest point from Indonesia all the way to Colombia. This ocean is 12,300 miles wide, which is more than five times the diameter (直径) of the moon.
Cold, hot and deep
In the colder parts of the ocean, one finds large icebergs (冰山). In fact, one iceberg can give a million people drinking water for five years. In the deepest part of the ocean, the water may be only 2~4℃, except that coming out of the seafloor. It can reach up to 400℃.
Gold in seawater
Did you know that most of our gold is in our world's oceans? The National Ocean Service says there is about 20 million tons of gold suspended (悬浮) in the seawater. There is also gold under the seafloor, but it is still difficult for humans to dig (挖) them out.
()7. What does "It" refer to?
A. The seafloor.
B. The iceberg.
C. The water coming out of the seafloor.
D. The deepest part of the ocean.
()8. What's the diameter of the moon?
A. About 12,300 miles.
B. About 2,460 miles.
C. About 61,500 miles.
D. About 80,000 miles.
()9. How does the writer introduce the ocean?
A. By using numbers.
B. By giving examples.
C. By exchanging views.
D. By asking questions.
()10. What can we learn from the passage?
A. Oceans cover 30% of the earth.
B. Humans can dig out much gold under the sea.
C. Oceans give us most drinking water.
D. Humans depend a lot on oceans.

7-10 CBAD