How was one [living in France] supposed to know whether or not to worry about a radioactivecloud?
怎能知道，[在法国生活]的人们应不应该为放射性尘埃担心呢？
2
In its early stages the rain was augmented by the small water droplets still descending from the radioactivecloud.
开始时，从放射性云下沉的小水滴使雨势增大。
3
In the early morning of April 26th 1986, an explosion at the plant released a radioactivecloud that spread over large swathes of Europe and western Russia.