Scientists in the United States have developed a method that may help to predict earthqua

Scientists in the United States have developed a method that may help to predict earthquakes earlier. They say it could give people who live in deadly earthquake areas enough warning to leave before an earthquake occurs.
Currently, the most modern systems for predicting earthquakes find them only a short time before the event. Like most strong earthquakes, Wenchuan earthquake in 2008 and Haiti earthquake in 2010 were not identified early enough for people to flee the area, killing hundreds and thousands of people.
But scientists who study earthquakes are reporting that new technology could measure very small changes in the Earth’s surface.
Scientists performed experiments along California’s San Andreas Fault, an area famous for its earthquakes. Highly sensitive electrical devices are placed about one kilometer below ground in two different places. The devices were able to measure even small changes in air pressure on the Earth’s surface. The scientists say such changes are caused when rocks pushed together, forcing air out of small cracks in the rock.
Two earthquakes hit the area in late 2005. The first took place on Dec.25. A smaller earthquake struck five days later. The scientists noted changes in the earth’s surface about ten hours before the first quake struck. That quake measured three in intensity(强度). They then found similar changes taking place two hours before the other quake struck five days later.
If additional tests confirm the changes are linked to earthquakes, the scientists believe their equipment could be used for early warning systems. A system that provides a warning signal ten hours before a major earthquake could help move people from the area and save lives.
The scientists now hope they can find earthquakes with even greater intensity by placing their equipment deeper in the ground.
71. What’s the best title for the passage?
A.A new way to help predict earthquakes.
B.The earthquakes in the world
C.A better understanding of earthquake
D.Scientists and modern systems of earthquakes
72.If the new method does work,     .
A.fewer earthquakes will break out
B.rescue workers can save more buried people in ruins
C.a warning can be given at least ten days before the major earthquake
D.fewer people will be killed in an earthquake
73.According to the passage, the devices can predict the earthquake by    
reaching the center of the earthquake
detecting the temperature changes in the earth’s crust
measuring changes in air pressure on the Earth’s surface
recording sound waves under the ground
74.We can infer from the passage that     .
the equipment is perfect enough to be used in practice
it’s unknown if greater earthquake can be predicted by the equipment
the deeper the equipment is placed, the more accurate the measurement is
the equipment has helped save many lives in the earthquake in Haiti .
75.How many earthquakes are mentioned in the passage?
A. One           B. Two           C. Three         D. Four71---75   ADCBD