Give the correct form of the word in brackets to complete each sentence. 1. A lot of toys encourage children’s ___________________. (imagine) 2. The factory has provided cheaper ___________________ lately. (produce) 3. Burning coal is an ___________ way of heating a house. Gas is much cheaper. (economy) 4. According to some scientists the earth is losing its outer atmosphere because of ______ . (pollute) 5. She has one of the biggest art ________________________ in Britain. (collect) 6. ________________ has caused many so-called man-made disasters. (forest) 7. ____________ often walk through the streets shouting or singing about something they sell. (cry) 8. Gas and oil ____________________ always increases in cold weather. (consume) 9. The police are interested in the sudden _________________ of the valuable painting. (appear) 10. He claimed that his _______________________ had caused him to become a criminal. (bring up)