单项选择题 In his The History of the Decline and Fall of the Roman Empire, Edward Gibbon lists some reasons for the rise of Christianity. Which one of the following is NOT on his list? A、The doctrine of a future life. B、The pure and austere morals of the Christians. C、The discord of the Christian group. D、The miraculous powers ascribed to the church.

问答题 由同步观测基线构成的闭合环称为（       ）。

判断题 资源教室最重要的资源是资源教师