Using the Past Participle

 

Choose the correct verb form for each sentence:

 

  1. All magnetic fields are (create created) by a moving electric charge.*
  2. Scientists (base based) their theories on observations.
  3. By the 1950s, scientists had (observe observed) dozens of new kinds of particles coming out of collisions of cosmic rays with nuclei.
  4. The transfer of photons between (charge charged) objects creates the electromagnetic force that, among other things, holds electrons in their orbit.
  5. Venus is (shroud shrouded) by clouds, but has been (map mapped) by radar from orbit.
  6. Cataclysmic explosions (rip ripped) through the cores of galaxies, spewing huge jets of material hundreds of thousands of light-years into space.
  7. The 1989 San Francisco earthquake was just one of countless shocks (trigger triggered) by the inexorable movement of two tectonic plates.
  8. When molten rocks (solidify solidified), the grains are (lock locked) in, and the rock "remembers" where the north pole was when the cooling (occur occurred).
  9. All life is (base based) on the same genetic code.
  10. Genetics is the branch of science (devote devoted) to studying how traits are passed from parents to their offspring.
  11. If you reflect on the fact that everything chemical in your body is (manufacture manufactured), (move moved), (modify modified), and (use used) by proteins that are (build built) from scratch from a sequence of amino acids precisely (dictate dictated) by the DNA sequence, you will see why we say that DNA holds the secret of life.
  12. Millions of Africans in hundreds of lakeshore towns and villages are (affect affected) by the changing ecology of Lake Victoria.
  13. Now the lake's shoreline is being (strip stripped) of trees, resulting in soil erosion and more lake (damage damaged).
  14. Humans, unlike other species, have (learn learned) to (shape shaped) and (alter altered) their environment in remarkable ways.
  15. Science is a great human adventure, with formidable challenges and priceless rewards, (unimagine unimagined) opportunities and (unparallel unparalleled) responsibilities.

 

*Example sentences drawn from Science Matters, Achieving Scientific Literacy, by Robert M. Hazen and James Trefil. Anchor Books, 1991.

 

Answer Key

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