总的来说，彗星的冰物质可能不是地球上水的主要来源。但在该领域，目前尚很少有肯定的认识。

In short, icy cometary material probably has not been important in providing water for the earth's oceans, but there is little sure knowledge in this field.

youdao

总的来说，彗星的冰物质可能不是地球上水的主要来源。但在该领域，目前尚很少有肯定的认识。

In short, icy cometary material probably has not been important in providing water for the earth's oceans, but there is little sure knowledge in this field.

youdao