考博考试

【单选题】 No one realized the cause of the deterioration of the world agricultural commodity market because ______.
A．there was a long interval between cause and effect
B．the weather was difficult for us to forecast
C．weather forecasts were inaccurate
D．ecologists didn't exist until modem times

网考网参考答案：A
网考网解析：
根据第二段最后一句话，由于结果较原因有一段时间的时间间隔，所以直到农产品市场收到严重影响，人们才知道其起因。 查看试题解析出处>>