AVTC4-RW-U7-p.131

The universe is ______ large, so there is a chance that there could be other forms of life.

• extreme

• extremely 

• a bit

• a little

Scientists have always been interested to know if life ______ outside of Earth.

• disappear

• disappears

• exist

• exists

Scientists have speculated about the possibility of parallel _______.

• universes

• universe

• planet

• star

Underwater cave exploration can be 

_______ and dangerous, and divers often risk their lives on expeditions.

• challenging

• challenge

• difficulty

• risk

Divers have to come back up to the ______ before they run out of oxygen.

• sea

• surface 

• sink

• shell

The bottom of the Mariana Trench is completely dark and very cold, but there may still be some ______ that are able to live there.

• creature

• creatures 

• people

• animal

We want clean rivers and lakes, where you can swim without _____ to your health.

• risky

• risks

• risk-takers

• risk

My passport _____ next month - I must get it renewed.

• runs out

• run out

• runs out of

• run out of