On 8th July, 1947, an army officer reported a crash at the Rosewell base in New Mexico, USA. .... Within hours, people from the base were saying a UFO had crashed there. But later the same day,.......

请问此处为何要用过去进行时呢? 一般过去时可以吗? Thanks♪ノ

过去进行时表示在过去某个时候不断发生的事件,即当时大家都在说某事,一会这个说,过一会那个又说,反复发生。

不要试图改为一般过去时。要学习这种进行体的使用方法。

再给你举一个类似例子。

Nowadays,people are dying of cancer.

现在,不断有人因癌症死亡。(近期一段时间不断反复发生的事件。)