useful- something that is designed to help
lose- no longer able to use
adult- a person who is fully developed or grown
child- a boy or girl under the age of 16
mature- old enough to understand why something is happening
understand- to know what something means
technique- a way of doing something so it works
concept- an idea
punishment- a penalty because of something you did
misbehavior- acting badly or doing something you should not do