仔细观察下面这枚“国家节水标志”，准确理解标志的含意，然后在下面一段文字的空格处填写适当的文字，使上下文句意衔接自然。（每句不超过15个字）

“国家节水标志”由____组成。绿色的圆形（标志中圆形背景实际为绿色）代表地球，象征节约用水是保护地球生态的重要措施。标志留白部分像一只手托起一滴水，手是拼音字母JS的变形，寓意节水，表示节水需要____；手又像一条蜿蜒的河流，象征滴水汇成江河。水和手的结合像心字的中心部分（去掉两个点），且水滴正处在“心”字的中间一点处，寓意着____。

微风吊扇通电后扇叶转动，使微风吊扇转动的工作原理是____．拔下插头，在插头处接发光二极管，用手旋转叶片，发光二极管发光，这是____现象，人们利用这一原理制成了____．

根据短文内容，选择正确答案。

    Many children act in TV shows. They work several hours every day, so they cannot go to regular school. How do they get their education?

    In Hollywood many TV shows are made. About forty teachers give lessons for the children in the shows. They teach wherever their pupils are working. The teachers' job is very important. They are responsible for making sure that the children work only the permitted hours each week. They are also responsible for making sure that the children learn the required subjects. They make sure, too, that the children get enough rest and play, along with their education.

Child actors are required to attend classes twenty hours each week. California law says they must be taught from September to June. If they do not make much progress in school, they are not permitted to continue working in TV shows. TV children are usually good pupils, and most of their teachers like this special kind of work. Their classes are held in some wonderful places. Sometimes the “classroom” is a Mississippi riverboat. Sometimes it is the inside of a spaceship. Often the pupils become famous stars.