题目内容：

Until recently, scientists had mapped only about 20 percent of the sea floor. But our knowledge of the deep seas is changing because of information from satellites. Scientists have produced a new map that provides a detailed picture of the oceans. The map is expected to help oceanographers (海洋学家), industry and governments.

The new map is twice as detailed as the map made 20 years ago. David Sandwell is a geophysics professor at the University of California. He and other scientists worked on the mapping project. He says they turned to space to look deeper into the ocean.

The scientists collected and studied information from two satellites. Some of the data came from the European Space Agency’s Cryo-2 satellite. It was placed in Earth's orbit to watch sea ice. The other satellite is the American space agency's Jason-1. It is studying the surface of the oceans. Scientists combined the satellite data with images gathered by sonar (声波定位仪) equipment on ships. Sonar works by sending sound waves through the water. When the sound waves hit an object, its presence is confirmed.

The new map shows the sea floor as it has never been seen before. It shows thousands of underwater mountains and places where continents pulled apart. It shows where earthquakes were active many years ago. They all are buried deep underneath the ocean floor.

David Sandwell says the map is a powerful tool for fisheries, those interested in protecting the environment and for oil exploration.

“The petrol exploration industry is interested in how to reconnect the continents, bring them back together tectonically so you can map the basins on one continental edge—say, Africa—and use that to establish where the similar basin would be on the other continental edge in South America.”

If scientists know that information, they may be able to find oil fields. The new data also will help scientists improve their estimates of ocean depths. This information can help ships travel safely and improve military operations and scientific projects worldwide.

Mr. Sandwell thinks scientists will make many more discoveries as they examine the new map and the information it provides.

1.Which one is not mentioned about the benefits brought by the new map?

A. Fisheries.    B. Scientific projects.

C. Ship manufacture.    D. Oil exploration.

2.What can we know about the new map?

A. It shows where earthquakes will happen.

B. It will be helpful to industry and governments.

C. It is three times as detailed as the old one years ago.

D. It shows the sea floor as it has ever been seen before.

3.The text is likely to appear in _________.

A. a newspaper    B. an advertisement

C. a science magazine    D. a finance report

4.Which of the following can be the best title for the text?

A. The detailed picture of the oceans

B. Underwater mountains and places

C. More discoveries about the oceans

D. Scientists create new maps of ocean floor