earth前要不要加the？

earth前要不要加the？

当地球讲的时候，需要加。当土壤讲的时候，不加

People used to think the earth was flat.

人们曾经认为地球是平的。

People used to believe the earth was flat.

人们一度认为地球是平的。

There were low banks of earth between the rice fields.

稻田之间有低矮的田埂。