Possibly including a "water planet," with an underwater city, and a "city planet," with the whole planet built over.

可能包括一个“水的星球”，以及一座水下城市，和一个“城市星球”，整个星球都是城市。

youdao

Scientists think there was probably water on the planet long ago.

科学家们认为很久以前在那个行星上可能有水存在。

youdao

To be able to support life, the new planet would need not only to have water, but it would also need to be solid.

为了能够维持生命，这个新的星球不仅要有液态水，而且它的土表还必须是固态的，就像地球这样。

youdao

His theory was that Martians were trying to bring water to the warm areas near the equator of the planet.

VOA: special.2010.07.11

Water exists on Earth and the planet Mars.

VOA: special.2009.09.30

And the world's insatiable appetite is depleting the planet's fisheries and using up land and fresh water at an alarming rate.

VOA: standard.2010.06.04

Lucas' clones are created by strange-looking aliens on a fantastic, stormy water planet.

FORBES: Scientists Fret Over 'Clones'

"The results suggest that water was incorporated during the formation of Mars and that the planet was able to store water in its interior during the planet's differentiation, " Hauri said.

MSN: Scientists say parts of Mars interior are as wet as Earth's

He has a point: Polluted water is the planet's deadliest foe, killing 14, 000 people a day, according to the World Health Organization.

FORBES: Magazine Article