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 hits. Currently, the most modem systems for predicting earthquakes find them only a short time before the event. Like most strong earthquakes, the one that hit southwestern China in May wasnot identified early enough for people to flee the area. That earthquake killed sixty-nine thousand people. But scientists who study earthquakes are reporting that new technology could measure very small changes in the Earth's surface. Their report was published this month in Nature magazine. Fenglin Niu is a seismologist with Rice University in Houston, Texas. He and his team performed experiments along California's San Andreas Fault, an area famous for its many earthquakes. The team placed highly sensitive electrical devices 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 push together, forcing air out of small cracks in the rock. When this happens, seismic waves travel taster than usual through the rock. The experiment was performed near Parkfield, California. Two earthquakes hit the area in late two thousand five. The first took place on December twenty-fifth. 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. They then found similar changes taking place two hours before the other quake struck five days later. The earthquake in China rated seven point nine in intensity. 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 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.
单选题
What is the limitation of current earthquakes predicting system?
【正确答案】
A
【答案解析】第二段第一句：Currently, the most modern systems for predicting earthquakes find them only a short time before the event(目前，最先进的系统只能在地震发生前很短的时间内预报)，显然A为正确答案。
单选题
Compared to former predicting systems, what is the improvement of the new technology?
【正确答案】
B
【答案解析】文章的第二段揭示出目前预报系统的不足，紧接着第三段用“But”转折：研究地震的科学家们报告说新的技术能够测量出地表非常细微的变化(scientists who study earthquakes are reporting that new technology could measure very small changes in the Earth's surface)。所以B选项为新的预报系统的改进。
单选题
In ______, the experiment was performed to test the new predicting system.
【正确答案】
D
【答案解析】由题干关键词“experiment”定位到第四段：He and his team performed experiments along Califomia's San Andreas Fault, an area famous for its many earthquakes. 他FenglinNiu和其团队沿着因地震而出名的加州的圣安德烈亚斯断层做了实验)。A选项只指出是加州而没有指出具体的位置，所以正确答案是D。
单选题
How do the new predicting devices work?
【正确答案】
A
【答案解析】文章第五段的大意为：实验组将高感电气设备放置于地下一千米的两个不同位置，这些设备能测量出比较气压的气压变化，科学家说这些变化是由岩石挤压一起而导致的，岩石相互挤压迫使空气从岩石的细小缝隙中跑出，这样地震波通过岩石的传播速度比平时更快。只有A选项By measuring the seismic waves caused by rocks' pushing together(通过测量由于岩石挤压一起而产生的地震波)与第五段的大意相符，因此该题正确答案为A。
单选题
Which, of the following is not true according to this passage?
【正确答案】
D
【答案解析】由D选项定位到文章最后一段：The scientists now hope they can find earthquakes with even greater intensity by placing their equipment deeper in the ground(科学家们现在希望通过将设备放入地下更深处以能发现更大强度的地震)。目前，这只是科学家们的希望，还没有得到证实，所以D选项的说法错误，该题的正确选项为D。