The earth revolves both round the sun and on its own axis.

地球既。

Mars takes longer to revolve on its axis than the earth.

火星一周的时间比地球长。

The earth rotates on its axis once every 24 hours.

地球每24小时依其轴心一次。

The spinar is a gigantic machine converting gravitational binding energy into electromagnetic radiation by means of rotation.

旋体是一架通过把引力束缚能换为电磁辐射的巨大机器。