There will be a period when your child will begin to be exposed to certain things you may not approve of or that may have happened already. I am not talking about the world, itself. I am talking about the Internet or television.
Your child may be a preschooler who knows how to navigate on the computer which exposes him or her to programs that may or may not be appropriate. Your child may use the TV remote control which exposes him to inappropriate viewing.
Use parental controls on the computer and television. You, as a parent, decide what kinds of websites and shows to block when your child is utilizing the technologies. You will need to create a certain password that your child cannot know or guess it. Be sure to pick a password that you can easily remember, write it down, and hide it in a safe place.
If your child does see something inappropriate on television or the computer, be sure to briefly talk about what he or she saw. Explain why it is inappropriate. It is up to you to decide how detailed you should be. Take your child's age and interest into consideration.