题目

Children lie on couches or sit on floors, nearly hypnotized(迷住) by all kinds of messages coming from the television. This scene has become all too familiar. Increasingly, young children are adopting a watching-TV lifestyle, at s stage in life when activity is important to their growth. Furthermore, family time is being destroyed by too much TV time. Here are some facts you need to know:    *Research shows that children spend between five and six hours per day watching TV, and they go to bed before having any communication with other family members.    *Time spent in front of a screen i注意观察、善于发现，正是由于具有这种敏锐的洞察力，丹麦物理学家奥斯特发现了（ ）A．电流具有热效应B．电流周围有磁场C．电磁感应现象D．通电导体在磁场中受到力的作用