如图所示的元件，在不移动元件位置，组成串联电路，且S控制L₁和L₂．

       Xiao Ming  is playing with his friend in front of a house. An old woman walks up to him. “My boy,” she asks., “ Is your mother at home?” “Yes ,” Xiao Ming says. The woman begins to ring（按） the door bell（门铃）, but there is no answer（应答）.
       She rings the door bell again. There is still no answer. The woman is not happy. She turns to Xiao Ming  and asks again, “Is your mother at home?” “Yes , she is.” Xiao Ming  answers. “But I ring the door bell twice and nobody（没人） comes to open the door,” the woman says.
“Oh, I'm sorry. This is not my house. My house is over there.”

 化学知识有助于我们正确认识、理智选择、科学生活，下列说法不正确的是（　　）