Bill Gates has a nice house on a hill by Lake Washington. Inside the house there are seven bedrooms, twenty four bathrooms, six kitchens and six fireplaces. It even has a theatre, a library, an exercise room and a swimming pool. You can say the house is very big. However, it doesn't look so big, because a large part of it is in the hills.

    The house is famous for many reasons. One is its large size, and another is its amazing electronic systems(电子系统).Before a visitor goes into the house, he or she gets a chip(芯片）at the gate. The chip sends information about the visitor to the electronic systems in the house. When the visitor goes into the house, lights are turned on automatically（自动地）.When the visitor goes from one room to another, he or she can hear music.

    Bill Gates began to build his house in 1990. It took him about 7 years to build it.