1. A lot of toys encourage children’s imagination. 2. The factory has provided cheaper production lately. 3. Burning coal is an uneconomical way of heating a house. Gas is much cheaper. 4. According to some scientists the earth is losing its outer atmosphere because of pollution. 5. She has one of the biggest art collections in Britain. 6. Deforestation has caused many so-called man-made disasters. 7. Street vendors often walk through the streets shouting or singing about something they sell. 8. Gas and oil consumption always increases in cold weather. 9. The police are interested in the sudden disappearance of the valuable painting. 10. He claimed that his upbringing had caused him to become a criminal.