If an asteroid hit Earth, it's average speed would be 30kilometers per second.

假如小行星撞击地球，它们的平均撞击速度将达到30公里每秒。

youdao

If an asteroid hit Earth, it's average speed would be 30kilometers per second.

假如小行星撞击地球，它们的平均撞击速度将达到30公里每秒。

youdao