单选题 One of the chief difficulties in accurate earthquake warning is that ______.

A、 earthquakes may take place in anywhere possible.
B、 earthquakes may happen at any unexpected moment.
C、 most earthquakes take place simultaneously and unexpectedly.
D、 the occurrence of earthquakes involves too many unforeseen factors.

【正确答案】 D

【答案解析】[精解] 本题为细节题。答案在文章第二段“Earthquake formation can be triggered by many factors”，认为地震的形成是由很多原因导致的。而A，B认为地震有可能在任何地点，任何时间发生，文章中没有提到；C 认为地震是不可预知的，这一表述不符合题义。