—Sorry. This is not the right ___________to invite me. I am too tired to walk.

—Although I live___________, I don't feel___________.

    How would you use a radio or a telephone if you had no electricity or batteries? These1bothered (使烦恼) British inventor Trevor Baylis. So in 1996 he2a wind-up (装有发条的) radio. It doesn't need electricity or batteries. You wind it up3hand. It plays for about an hour. Then, you wind it up4.

    Baylis also invented a mobile phone that is powered by5. The shoes contain (含有) a small battery that is powered when you6. This battery is connected to a mobile phone. These two simple inventions can bring modern7to all parts of the world.

    Baylis didn't have a university degree in engineering. In8, he left high school before graduating (毕业). He just loved9things to help people. He never knew10ideas would come to him. The idea for the phone came to him in a dream.

    Most cars run on gas. Gas cars work very well. But there is a problem. Cars that run on gas make the air dirty. The dirty air is not good for people, animals or trees. Gas cars make the air dirty for all living things. What can we do? We can drive electric cars!

    Electric cars do not use gas. These cars do not make the air dirty. These cars have batteries that power their motors (马达). The batteries can be charged (充电) many times. They can be used again and again. This makes electric cars great.

    But electric cars have problems too. They are slower than gas cars. They are also very quiet. This means that some people can't hear them when they go by. They may not think a car is coming. So they have to be careful.

    People are finding ways to make electric cars better all the time. Maybe one day all cars will be electric. That would be much better for the world.