Give the correct form of the word in brackets to complete each sentences.
1.A lot 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 claimes that his -------------- had caused him to become a criminal.(bring up)