The San Andreas fault is ______.A) an active fault systemB) a place where earthquakes

参考答案:

AA[试题分析] 细节题。[详细解答] 根据第四段第一句To answer the first question，scientists are looking very closely at the most active fault systems in the country，such as the San Andreas fault in California．的表述，不难判断A为正确答案。