Find and correct a mistake in each sentence.

1 The research on environmental problems should be speeded on. ________
2 Companies which break environmental rules must pay off. ________
3 Global warming is often put up to carbon dioxide (CO2) production. ________
4 The lava cloud that was created after the volcano eruption made it impossible for the planes to fly. ________
5 People in Western societies buy too much food and throw it off. ________