A college teacher once gave a lively class to his students.

He began by holding up a glass _______ some water in it. He held it up for all to see, and asked the students, "_______ do you think this glass weighs?"

"50g!" "100g!" "125g!" the students answered.

"I really don't know unless I weigh it," said the teacher, "but my _______ is what would happen if I held it up like this for a few minutes?"

"Nothing," the students said.

"OK. What would happen if I held it up like this for an hour?" the teacher asked.

"Your arm would begin to_______” said one of the students.

"You are right. Now, what would happen if I held it up for a _______?"

"You might have muscles (肌肉) stress. You could_______ move the arm," said another one.

"You might have no _______ in the arm, or paralysis (瘫痪),"said a naughty student,"You _______ go to the hospital for sure!"

"Very good. But during this period, did the weight of the glass _______?" asked the teacher.

"No," the students said.

"Then what ________ the arm ache and the muscles stress?"

The students were ________.

"No one knows?" the teacher asked, "Well, can you tell me how to________ it?'

"Put the glass down!" said one of the students.

"Exactly!" said the teacher."The problems of life are something like this. Think of them for a few minutes in your________ and you seem OK. Think of them for a long time and you begin to hurt. Think of them even longer and you will not be able to do anything. It's important to think of the challenges in your life,________ it's even more important to 'put them down' at the end of every day before you go to sleep. That way, you are ________—you wake up every day fresh and strong and can solve any problem that comes your way!"

The world is in great need of fresh water. About 97% of water on Earth is salt water. Man can only drink or use the rest which comes from rivers，lakes and the underground. The number of people in the world is becoming larger and larger，so we need more and more fresh water. Now water shortage (短缺) becomes a big problem. And people are trying their best to find more ways to get fresh water.

Then what can we do about it？Scientists have found some ways to turn salt water into fresh water. One important way is to boil (煮沸) sea water at a high temperature. In this way，we can make a lot of fresh water. But it often costs too much. And heating is not the only way to get fresh water.

People also have other ways，such as digging deep wells (井)，keeping rainwater and protecting rivers from being polluted.

Which way is better？I think to get the most fresh water with the least money is the best. And most importantly，everyone should take part in saving water. And it's not difficult. We should just try not to waste any water in our everyday life.

I feel that I’ve grown up and should make my own decisions, but my parents disagree. My mom still helps me choose what clothes to wear. My dad asks me to pay attention only to study. I know they do this out of love, but I feel controlled. What should I do?

Amanda

Your parents sound very strict. It’s hard to believe that your mom chooses what you wear. Are you a Barbie doll?

Try to take the first step when possible. Dress yourself before your mother has a chance to come in and choose your clothes. If she asks you to change, tell her you’ll be late for school.

You should also talk to her. Ask about her choices: What makes a set of clothes acceptable or unacceptable? Tell her you will follow her rules, but you want to make the choices. You are not in first grade. You are a young lady in high school.

As for your father, it’s difficult to argue with his mind. After all, he is not totally wrong. How strict is he? Does he lock you up with your textbooks? Are you allowed to have a hobby? Are you allowed to have a smartphone? Are you allowed to hang out with friends?

Such strict parents should know the law of diminishing returns（收益递减）. A weightlifter, for example, can only lift for an hour or two each day. If she does more, her muscles will not become stronger. She will just get tired. She may even hurt herself!

Our brains also have limits. Some violin teachers say you should only practice a new skill for 15 minutes each day. Our brains need to relax and understand new information. Our brains also have a basic need to socialize（社交）. Ask your father: what is the meaning of so much studying if it makes you feel unhappy?

Stay strong.

Daniel

Do you know which social app Chinese young people use a lot now?     81     Some users use Tik Tok (抖音) and Kuaishou. They think it is fun to share short videos about their lives, while others have other purposes as well.

A l2-year- old user named Elsa has about 2.7 million fans on Tik Tok. The girl has shared videos about her dancing studies since last July.     82     “I feel really glad to share happiness with people by short videos,” said Elsa.

As some videos are about the latest news, a group of users depend on them to get information. To some other users, they have a different purpose. “Because I can’t spend many hours watching a whole video and I’m not a very patient person,     83     I prefer to watch short videos of wonderful parts in programs,” said Wang Zhihao.

    84     “Killing time is the main reason for me to watch the short videos, but many are almost the same, so I think it is a waste of time. What’s more, I really don’t like the videos which show strange even dangerous things,” said Wen Nan, another college student.

Recently, something else has happened. Some videos are telling people what products are worth buying.     85     So they should think twice. Some short videos even sell bad products, but these sellers won’t let you get your money back.

Long time ago, a poor man had an orange tree. There     91     many oranges on the tree. One of them was as big as a football. He said, “This is the biggest one I     92     so far.” He decided to take it to the king. When the king saw the orange, he was so pleased that he gave him a lot of money for it. When a rich man     93     of it, he said to himself, “It’s only an orange. Why can the poor man     94     so much money? If I take my gold cup to the king. he’ll give me more money. When the king received the gold cup, he said, “What a beautiful cup! I     95     you something wonderful. Please take this great orange.”