Have you ever seen a bird fly high up in the sky?

你见过小鸟在高高的天空中飞翔吗？

The balloons somehow take the hydrant up into the sky and off the ground so that it flies high up into the sky.

这些气球以某种方式把消防栓带向天空，离开地面，这样消防栓就能飞上高空。