直到最近也没有人意识到，地球正受到来自太空的不可预测的猛烈撞击。
Until recently, nobody realized that Earth is exposed to unpredictable violent impacts from space.
气球从太空返回，直到落在海里。
The balloon moves back down from space until it falls down in the sea.
直到20世纪80年代末，也就是苏联发射和平号空间站的时期，人们才开始在太空中居住更长时间。
It wasn't until the late 1980s when The Soviet Union sent the Mir space station that people began to live in space for a longer time.
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