Sadness and happiness are often talked about by people in their spare time. Most people want themselves to be happy for ever, but few know how to find happiness. Others say if you own lots of money and success, you will be happy. However, money and success alone do notbring lasting happiness. A famous a Greek thinker, Aristotle, said, “Happiness depends upon ourselves.” That’s to say,we make our own happiness. Here are a few suggestions to help you be happier.

The first secret of happiness is to enjoy the simple things in life. Too often, we spend so much timethinking about the future. For example, getting into college or getting a good job, which we fail to enjoy thepresent. You should enjoy life’s simple pleasures, such as reading a good book, listening to your favorite music, or spending time with close friends. People who have several close friends often live happier and healthier lives.

Another secret to living a happy life is to be active. Many people go dancing or play sports. People can forget about their problems and only think about the activities. Finally, many people find happiness in helping others. Studies show that people feel good when they spend their time helping others. If you want to feel happier, do good things for someone. You can help a friend with his or her studies, go shopping or help out with some things around the house for an elderly person.

If you do above, you will be happy.

Last month, a common graduation ceremony (毕业典礼) was held in Tianjin University, but it received much attention. Xue Minxiu, born in 1937, graduated with excellent grades after working hard for 4 years.

Going to a university has always been a dream for Xue. But for some reasons, she didn't have the chance when she was young. Even so, she never forgot her dream. In 2014, she was accepted by Tianjin University and finally her dream came true. Since then, Xue has been a model for the people around her. She got up at 5 o'clock every morning. Then she studied for a while before brushing teeth and having breakfast. Her room was filled with books and newspapers. Wherever she went, she would take books with her.

In fact, for her age, Xue had many difficulties during the four years. But nothing could stop her. Whenever she had problems, she would either solve them by herself or ask teachers for help. Through her hard work, she passed the exams and was named "a star student" during the first period of her college life.

"I think the true meaning of our lives is to challenge (挑战) and improve ourselves whether we are old or young. Xue said at the graduation ceremony. "For me, learning something I enjoy is a lifelong journey. I want to thank Tianjin University for giving me the chance to achieve my dream. Our lifetime is short, so we should make good use of it."

For people, it’s not surprising that we can open a door, lift a heavy box and control ourselves while walking in the snow. But can a robot do these? Well, Google’s new robot, Atlas, can not only do these things, but it can stand up if it falls down. Although the robot may be slow and clumsy, it was created mainly to work in dangerous places for humans.

Now, robots are much smarter than you might imagine. On March 9 this year, AlphaGo, an artificial intelligence (人工智能) program made by Google’s DeepMind, challenged top professional Go player Lee Sedol from South Korea. And AlphaGo beat Lee at last.

AI is when computers or computer software is able to have intelligent behavior, such as thinking or acting like a human. In our daily life, we already use AI in many ways, such as Apple’s Siri and search engines like Baidu and Google.

Some people may worry whether computers are now smart enough to beat us at everything. But experts say that is not the case. Real life problems can be more difficult than the Go game. For example, humans can watch a person throw down a cup of coffee and know that the result will be a mess on the floor. A computer program would have to know the size of the cup, the height of the cup from the floor and many other things to find out the result. But we never know what will happen in the future.

On November 5th, 1872, the Mary Celeste left New York to sail to Italy. The captain, his wife and daughter and seven sailors were on board. But something terrible happened. The captain of another ship found the Mary Celeste floating (漂浮) in the middle of the sea on December 4th, 1872. The captain, his family and the sailors were not on the ship and were never found.

What happened? Why did the sailors and passengers leave the ship? The Mary Celeste was not broken. Everything was good. There was no fighting, no fire and no smoke sign. There was still plenty of food and drinking water left. There were signs that the captain, his family and the sailors had left the ship in a hurry. We could tell all these because there was half-eaten food on the table. The sailors also left all their clothing behind. Even their shoes were beside their beds.

How and when did the people leave the ship? Some people said that the lifeboat (救生艇) was still on the ship but others said it was missing. The captain’s diary was found on the ship and the last entry (记录) was made on November 24th. So, we could only guess that the happening time was between November 24th and December 4th.

An investigator (调查者) went aboard the ship several times to search for the answers to all these questions. But he could not find any. No one else could solve the mystery.

There is a song we all can sing––March of the Volunteers (《义勇军进行曲》). It’s our national anthem (国歌). We learn it     74     the beginning of primary school and sing it at every flag-raising ceremony (仪式). Now, there is a law to protect the song.

On Sept. 1, 2017, the government     75     the National Anthem Law. It tells us     76     to sing or play the song correctly, requiring all Chinese to respect it. The law will take effect from Oct. 1, reported People’s Daily.

According to the law, the song will only be allowed to play at nine situations, such as major sporting events and flag-raising ceremonies. We shouldn’t use     77     at personal funerals (葬礼) or as background music in public places.

Moreover, the law requires Chinese to be     78     when singing the song, so we can neither joke about the song     79     change the song’s words. If someone breaks the law, he or she can be detained (拘留) for up to 15 days.

Many foreign     80     also have laws for their national anthems. For example, in the USA, people should put the right hand over their hearts     81     singing the song. In Russia, the national anthem must be played on television and radio before the start and the end of broadcasting (节目播出).