Men have always wanted to fly like birds. Birds can fly easily because they are light, but men's bodies are heavier.

    Men first went up into the air in balloons. These were big bags, and they were filled with gas. Hydrogen (氢气) is a useful gas for balloons. It is lighter than air. Helium is also lighter than air, but it costs a lot of money. So balloons are usually filled with hydrogen.

Balloons have to fly with the wind as they have no engines (发动机) to drive them. Later, men made airships. They are balloons with engines. They are also filled with hydrogen.

    Aircrafts (飞机) with wings now take people across the world. Powerful engines drive these machines across the sky. Some of the engines are like the engines of cars, but they are more powerful.

    There is another kind of engine, we call it the jet (喷射) engine. An English engineer invented the jet engine. At the same time, Germans were also building a jet engine. In May 1941, the English engineer's new engine was fixed in an aircraft, and the aircraft flew quite well.

    Jet engines are very powerful. Usually two to four are enough for an airplane, but some big aircraft need six. Anyone in a moving jet plane can feel the power of the engines. Jet planes can travel faster than sound. As a flying jet plane leaves its noise behind, we do not hear it until it has gone.

    On Christmas Eve─the night before Christmas Day─children all over Britain put a stocking at the end of their beds before they go to sleep. Their parents usually tell them that Father Christmas will come during the night.

    Father Christmas is very kind and hearted. He gets to the top of each house and climbs down the chimney into the fireplace. He fills each of the stockings with Christmas presents.

    Of course, Father Christmas isn't real. In Jim and Kate's house, "Father Christmas" is really Mr Green. Mr Green doesn't climb down the chimney. He waits until the children are asleep. Then he quietly goes into their bedrooms and fills their stockings with small presents. When they were very young, Mr Green sometimes wore a red coat. But he doesn't do that now. The children are no longer young, and they know who "Father Christmas" really is. But they still put their stockings at the end of their beds.

B

    In choosing a friend, one should be very careful. A good friend can help you study. You can have fun together and make each other happy. Sometimes you will meet fair-weather friends. They will be with you only if you have money or luck, but when you are down, they will run away. How do I know when I have found a good friend? I look for certain qualities of characteristic, especially understanding, honesty and reliability (可靠).

    Above all else, I look for understanding in a friend. A good friend tries to understand how another person is feeling. He is not quick to give his opinion. Instead, he tries to learn from others. He puts himself in the other person's place, and he tries to think of ways to be helpful. He is also a good listener.

    At the same time, however, a good friend is honest. He does not look for faults (过错) in others. He notices their good points. In short, a friend will try to understand me and accept me.

    Another quality of a friend is reliability. I can always depend on (信赖) a good friend. If he tells me he will meet me somewhere at a certain time, I can be sure that he will be there. If I need help, he will do his best to help me. If I am in trouble, he will not run away from me.

    There is a fourth quality that makes a friend special. A special friend is someone with whom we can have fun. We should enjoy our lives, and we would enjoy our friendship. That is why I especially like friends who are fun to be with. A good friend likes the same things I like. We share experience (经验) and learn from each other. A good friend has a good sense of humour, too. He likes to laugh with me. That is how we share in the joy of being friends. And I know that he is looking for the same quality in me.

    When I meet someone who is reliable, honest, and understanding, I know I've found a friend!

2019 Beijing International Horticultural Expo

    Time: April 29~October 7

    Theme: Live Green, Live Better.

    Many flowers and herbs from both home and abroad are on display at the expo.  There are also lots of wildflowers.

    Around 110 countries and international organizations take part in the expo.

    The expo has 4l outdoor display centers and about 2, 500 activities.

注: International Horticultural Expo世界园艺博览会