Write the correct form of the given words.
17. It is possible that we find ______________ things on another planet. (LIVE)
18. I find her story about UFOs hardly ______________. (BELIEVE)
19. Environmental pollution has led to the ______________ of many species of plants and animals from our planet. (APPEAR)
20. Many UFO ______________ have been recorded by the United States government. (SIGHT)
17. It is possible that we find living things on another planet.
18. I find her story about UFOs hardly believable.
19. Environmental pollution has led to the disappearance of many species of plants and animals from our planet.
20. Many UFO sightings have been recorded by the United States government.
1 living
2 believable
3 disappearance
4 sightings