19. Use the verbs in brackets in either Active Voice or Passive Voice.

Black holes are some of the strangest things in space. A black hole 1) (sucks) in anything that gets by. Nothing escapes from a black hole. Not even light. Everything 2) (is pulled) together. The reason is gravity. Gravity is aforce that pulls one thing to another. Gravity is the force that 3) (holds) you down on Earth. When you jump up, you 4) (are drawn) back by gravity. The Moon 5) (is made) to orbit Earth by gravity. The more matter 6) (is packed) in a star, planet, moon, or other object, the stronger is its gravity. Gravity makes an object with more matter 7) (pull) an object with less matter toward it. The Sun's gravity pulls on itself our Earth. The Sun 8) (is orbited) by Earth. The matter that makes up an iron ball 9) (compress) much tighter than the matter that makes up a bag of feathers. A lot of matter 10) (goes) into a black hole. Astronomers and physicists think black holes 11) (are born) from dying stars. Under the force of gravitation the star 12) (is made) denser and denser to turn into a black hole.