Gap-fill exercise

Fill in all the gaps, then press "Check" to check your answers. Use the "Hint" button to get a free letter if an answer is giving you trouble. You can also click on the "[?]" button to get a clue. Note that you will lose points if you ask for hints or clues!

1. W is the most commonly used power source.
2. Energy sources are classified into two groups: r and non-renewable.
3. N energy sources are called so because their supplies are limited.
4. Geothermal energy comes from with the E.
5. Solar p collect sun energy to make electric power.