单选题 Children in the United States are exposed to many influences other than that of their families. Television is the most significant of these influences, because the habit of watching television usually begins before children start attending school. And by the time that the average child finishes high school, he or she will have spent 18,000 hours in front of a television set as opposed to 12,000 hours in a classroom.
Parents are concerned about these figures. They are also concerned about the lack of quality in television programs for children. The degree of violence in many of these shows also worries them. Even if it is unreal — a cartoon cat beating up a cartoon mouse with a baseball bat — this violence may have a negative effect on the young minds exposed to it. Studies indicated that, when children are exposed to violence, they may become aggressive or insecure.
Parents are also concerned about the commercials that their children see on television. Many parents would like to see fewer commercials during programs for children. And some parents feel that these shows should not have any commercials at all because young minds are not mature enough to deal with the claims made by advertisers.
Educational televisions has no commercials and has programs for children that many parents approve of. The most famous of these is "Sesame Street", which tries to give preschool children a head start in learning the alphabet and numbers. It also tries to teach children useful things about the world in which they live.
Even though most parents and educators give "Sesame Street" and shows like it high marks for quality, some critics argue that all television, whether educational or not, is harmful to children. These critics feel that the habit of watching hours of television every day turns children into bored and passive consumers of their world rather than encouraging them to become active explorers of it.
We still do not know enough about the effects of watching television to be able to say whether or not it is good for children. Until we do, perhaps it would be wise to put a warning on television sets such as the one on cigarette packages: "Caution: Watching Too Much Television May Be Harmful to Your Child's Developing Mind./

【正确答案】 D

【答案解析】细节题。本题事实上是对文章中“These critics feel that the habit of watching hours of television every day turns children into bored and passive consumers of their world rather than encouraging them to become active explorers of it.”的理解，句子表示的意义为“孩子每天看儿小时电视的习惯，会使他们变成这个世界无聊、消极的消费者，而不是鼓励他们对这个世界进行积极探索。”因此，[D]选项正确。