20

We launch space craft and know a lot about our universe, the nearest planets and stars. However, we know surprisingly little about the place we live in, and one of the greatest mysteries of the planet is the ocean.

(greatest - самая великая. Степени сравнения прилагательных)

GREAT

21

It occupies a vast area and there are still so many mysteries hidden in its depths!

(it occupies - она занимает. Present Simple)

OCCUPY

22

Everyone knows that life first appeared in the water. Later some of the creatures came out of the ocean onto the land, and the others stayed there.

(came out - вышли. Past Simple, Неправильные глаголы)

COME

23

The ocean has changed a lot since those prehistoric times but it is still a place where life is rich and diverse.

(has changed - изменялся. Present Perfect)

CHANGE

24

Nowadays the ocean is inhabited by millions of amazing creatures too.

(is inhabited - населён. Present Simple Passive)

INHABIT

25

They are tiny and huge, and some of them look as fantastic as aliens from other planets.

(some of them - некоторые из них. Местоимения) 

THEY

26

Marine researchers wish they could get to the bottom of the ocean to explore it, but unfortunately it is not possible now.

(could - могла бы. Модальные глаголы)

CAN

27

There is no technology yet that can allow people to go so deep under the water.

(There is no - не существует. Present Simple)

BE

28

The ocean is still keeping its secrets.

(its - его. Местоимения) 

IT