Jane's mother was about seventy, and Jane and her husband wanted to give the old lady a nice present for her birthday. She liked , so Jane bought a small electric machine（电器）. It could make tea and then in the morning. She brought it to her mother on her birthday, and showed her how .

"Before you go to bed, put tea and water in it," she explained to her mother, and don't forget . When you wake up in the morning, your tea will be ready. "

After a few days, the old lady telephoned her daughter and said, "Jane, there is one thing I don't understand. Why do I go to bed to make tea? Can't I have tea in the afternoon or in the evening?"

If we try to think of the most important inventions in the 20th century, I think electricity may (is) the most important, in a way. It plays important part in the development(发展) of the modern world. It can affect (影响) everyone's life. When the electricity (go) off, we call it a power cut. Can you imagine what (we) life will be like (with) electricity? Almost everything (stop). Electrical appliances(电器) can't work; traffic lights are dead; many workers must stop (work), and so on. Electricity is so (importance), it is also limited(有限的). should we do? At least (至少), we mustn't waste electricity.

—First, you have to ________ your computer ________ the Internet.

—No, I can't. I think they're having a meeting in the playground.