单选题

A Great Quake Coming?

Everyone who lives in San Francisco knows that earthquakes are common in the Bay Area--and they can be devastating．In 1906，for example，a major quake destroyed about 28,000 buildings and killed hundreds，perhaps thousands of people．Residents now wonder when the next“Big One”will strike．It's bound to happen someday．At least seven active fault(断层)lines run through the San Francisco area． Faults are places where pieces of Earth's crust(地壳)slide past each other．When these pieces slip，the ground shakes．
To prepare for that day，scientists are using new techniques to reanalyze the 1906 earthquake and predict how bad the damage might be when the next one happens．
One new finding about the 1906 quake is that the San Andreas fault split apart faster than scientists had assumed at the time．During small earthquakes，faults rupture(断裂)at about 2.7 kilometers per second．During bigger quakes，however．ruptures can happen at rates faster than 3.5 kilometers per second．
At such high speeds，massive amounts of pressure build up，generating underground waves that can cause more damage than the quake itself．Lucky for San Francisco，these pressure pulses(脉冲)traveled away from the city during the 1906 event．As bad as the damage was，it could have been far worse．
Looking ahead．scientists are trying to predict when the next major quake will occur．Records show that earthquakes were common before 1906．Since then，the area has been relatively quiet．Patterns in the data，however，suggest that the probability of a major earthquake striking the Bay Area before 2032 is at least 62 percent．
New buildings in San Francisco are quite safe in case of future quakes．Still，more than 84 percent of the city's buildings are old and weak．Analyses suggest that another massive earthquake would cause extensive damage．
People who live there today tend to feel safe because San Francisco has remained pretty quiet for a while．According to the new research，however．it's not a matter of“if”the Big One will hit．It's just a matter of when．

单选题 The San Francisco area is located above several active fault lines．
A．Right B．Wrong C．Not mentioned

单选题 The 1906 earthquake in San Francisco is the most severe one in American history．
A．Right B．Wrong C．Not mentioned

【正确答案】 C

【答案解析】[解析] 关键词为1906。依据此关键词，可在文中第一段第二句找到相关叙述：In 1906，for example，a major quake destroyed about 28,000 buildings and killed hundreds，perhaps thousands of people．(例如，1906年，一次大地震摧毁了28,000座建筑物并夺走了成千上万人的生命。)但原文中并没提到“是美国历史上最强烈的一次”，故此题为“未提及”的。

单选题 The highest speed of fault ruptures in the 1906 quake was more than 3.5 kilometers per second．
A．Right B．Wrong C．Not mentioned

【正确答案】 A

【答案解析】[解析] 关键词3.5 kilometers per second。依据此关键词，可在文中第三段最后一句找到相关叙述：During bigger quakes，however，ruptures can happen at rates faster than 3.5 kilometers per second．(但在更大的地震中，断裂速度可以高于3.5千米每秒。)因此可知，“最高断层断裂速度高于3.5千米每秒”的叙述是正确的，故此题为“正确”的。

单选题 Earthquakes rarely happened in San Francisco before 1906．
A．Right B．Wrong C．Not mentioned

单选题 San Francisco is fully prepared for another big earthquake．
A．Right B．Wrong C．Not mentioned

【正确答案】 B

【答案解析】[解析] 依据第六段第二句的叙述：Still，more than 84percent of the city's buildings are old and weak．Analyses suggest that another massive earthquake would cause extensive damage．(还有84%以上的建筑物又旧又不结实。分析指出下一次的大规模地震将会造成巨大的破坏。)所以“旧金山并没有做好充分准备。”故此题为“错误”的。