方程 是（      ）

    My three-year-old granddaughter, Tegan, went with her parents to a family gathering at the home of her other grandparents. Everyone was having a wonderful time visiting and catching up on all the latest family news.

    Like most children, Tegan was having a good time playing with all the toys that were different from her own and that were kept for children to play with at her grandparents' house. In particular, Tegan had found a little tea set and had begun pretending that she was having a tea party. She set up all the place settings and arranged her table with the great care and elegance that only a three-year-old can create. Meanwhile, her Daddy concentrated on conversation, and as he continued to chat with his family, Tegan would hand him a cup of "tea". Her Daddy, who always tries to participate in her games, would pause for a few seconds from his conversation, and say all the proper words and gestures for her tea party which would thrill Tegan. He would request two lumps of sugar. He would tell her how wonderful her tea tasted, and then he would continue his adult conversation with his family.

    After going through this routine several times, her Daddy suddenly awoke to reality as he had a flash of concern in his mind: "She is only three years old, where is she getting this 'tea' that I've been dutifully drinking?" He quietly followed her, without her knowing, and his fears were growing stronger as he saw her turn and go through the bathroom door. Sure enough, there she was stretching up on her tippy toes reaching up to get her 'tea' water out of the container of water that grandpa used to soak (浸泡)his false teeth!