如图所示，两个灯泡始终完好，当开关S断开时，两个灯泡都发光，当开关S闭合时，可能出现的现象是

喜马拉雅山的形成原因是（　　）

Teenagers growing pains

    Today, our students are facing many different problems and they want to ask some experts for help. Nancy says she feel stressed these days because of too much homework. She hasn't enough time to sleep for a long time and often falls asleep during the classes. John says he doesn't like to study because of the bad effect of computer games. Cindy says she gets fat because she likes to eat junk food and hardly ever takes exercise. Frank has the worst problem. He always fights with others as he doesn't know how to get on well with others and few of his classmates would like to talk with him.