How would you use a radio or a telephone if you had no electricity or batteries? This 1bothered（使烦恼）British inventor Trevor Baylis. Then he made a wind-up（装有发条的）radio. It doesn't need2or batteries. You wind it up3 hand. It plays for about an hour. Then, you wind it up again. Today it's 4 in South Africa.
Then in 1999, Baylis invented a mobile phone that is powered by5. The shoes contain（含有）a small battery that is powered when you 6. This battery is7 to a mobile phone. These two simple inventions can bring modern communication to all parts of the world.
Baylis didn't have a university degree in engineering. In 8he left high school before graduating（毕业）. He just loved9 things to help people. He never knew10 ideas would come to him. The idea for the telephone came to him in a dream.
Light and shadow（影子）are friends. They usually go together. We receive light every day. At the same time, we produce shadow.
Light cannot shine through you. Your body stops it from passing. There is a dark spot on the ground next to you. The light cannot reach the dark spot. This is your shadow.
At noon the Sun shines over your head. Your body stops very little light from reaching the ground.
We love light, especially sunlight. Without sunlight, life on the Earth is impossible. Most of us like to stand in the shadow of a tree in summer. But some people are afraid of their own shadow at night. They do not want to walk in a dark street. They do not want to see the shadow either. But still light and shadow usually go together.
Summer is just around the corner. It starts on June 21st or 22nd. For most kids, that means more time to play outside and have fun. Follow these tips to make sure you stay safe when you are enjoying the season. Sun safety
Many kids will spend hours playing outside in the summer dun. But be careful. The harmful rays(光线) of the sun can cause damage to your eyes. If you are out in the sun, be sure to wear sunscreen(防晒霜). You should also wear a hat and sunglasses that protect against the harmful rays.
__________
Make sure you follow water safety rules. Always swim with an adult watching you. If you don't know how to swim, you can take lessons. Rules about biking and skating
Biking and skating are good ways to exercise. To stay safe, always wear a helmet(头盔). It will protect your head if you fall down.
