A Cloud of Hope and Danger

    In 2050, a small cloud floats through the air in a hospital operating room(手术室). In the room a patient, suffering from cancer, lies on a table. The cloud surrounds (包围) the patient, her body and filling her lungs (肺). The cloud is not smoke or steam. It is made of millions of microscopic robots called nano-robots(纳米机器人). These tiny robots move from cell(细胞) to cell in the body, destroying the cancer cells.

    Fighting cancer with nano-robots is only an idea today, scientists say that it would be possible in the future. Using nano-robots for good purposes such as fighting disease or repairing the environment may be the to many of today's problems.

    However, nano-robots could be a risk as well. Since nano-robots are so tiny, they will have to work in large teams of many thousands to 'many millions. For this reason, nano robots will have to be programmed to build . Scientists will not have the ability to build millions of nano-robots one by one.

    This to reproduce(复制)is making some scientists worried. What if something goes wrong in the programming? Quite a lot of crazy nan-orobots would be far than any disease. Some people think that if they get out of control, nan-orobots could destroy the Earth.

    What should be done? Should we continuenan-orobots or should we search for other methods? This is one of the many difficult that we have to make in the future.

Mom often says, "Cooking is an important skill, and it can be fun!" But I had no interest in cooking at all  I met with a cooking app（应用软件）. There are different kinds of recipes（菜谱）in the app. They offer detailed instructions  users can follow them step by step. Most of them even include photos or videos, which are quite useful for beginners. Last week, I picked up a popular recipe to cook fish. When I  , it was exactly what I wanted and tasted delicious. Then I tried more recipes. Now I can cook a couple of  . I find cooking is great fun and it seems that I  cooking. My plan is to invite my friends over next weekend and show them my new skills. I hope they will like my cooking.

Today, we still have some environmental problems. As a middle school student, we should do something to improve more environmental .

On the one hand, we ourselvesdestroy the environment, such as throwing the rubbish about. We canpart in some commonweal（公益）activities to plant more trees, for the trees are good to our environment. On the other hand, if someone does harm to the environment, like spitting on the ground or stepping on the grass, we can stop them from so, If there's a factory which destroys the environment, we can tell the relative（相关）department or the police about it.

All in all,  we are students, we can still do a lot to protect our environment, and we should take action from now on.

Night came, noises calmed down and the Mexican sports center of the Olympics stood quiet in darkness.

Greenspan, the world famous reporter, found the center  after making the scenes where the marathon（马拉松）winners received the medals and marked the victory. It was time for him to return to the hotel for a rest. He was about to leave when he suddenly saw a bandaged man ran into the center with his right  bleeding. This man ran lamely（一瘸一拐的）out of breath, but he didn't  . After he ran along the runway for a circle and got to the   , he fell down on the ground.

Greenspan guessed this was a marathon runner. Feeling interested, he went over to ask why the runner wanted to run to the goal with  a difficulty. The young man  Kowari from Tanzania replied, "That my country sent me here from more than 20,000 kilometers is not to let me get off the mark in the competition, but to make me complete the game. I want to run to the goal,  I have fallen behind all other runners. I have a great goal  them. I will run to the goal. Though the audience（观众）won't cheer me any more, my motherland is watching me  from behind…"

Tears welled up in Greenspan's eyes. Soon, he  the most touching scene in the history of the Olympic Games to every corner of the world.

One day, a little boy came into a shop. He to the shop assistant(售货员) and said, "I'd like twelve exercise books of six cents each and nine pencils of ten cents each. How much are they?" The shop assistant wrote these down on a piece of paper and thought for a minute. Then she answered, "$1.62."

"If I give you $10, how much money will I get back?"

"You will get $8.38 for change. Here you are. These the things you want."

"No, thanks. In fact, I don't need to buy anything. This is math homework." The boy looked at the piece of paper and asked , "Can I take it away?"

Once upon a time, there was a shepherd. He kept many sheep. the day time, he herded (放牧) them outside; at night, he drove them into the sheepfold (羊圈) which was enclosed by dry grass and pegs.

One morning, the sheperd to herd the sheep and found one sheep lost. He then found that the sheepfold had been broken and there was a big . "The wolf must have stolen the sheep through the hole." He thought. "You'd better the sheepfold and mend the hole as soon as possible. "The neighbor advised him." The sheep has been lost. It's no use repairing the sheepfold." He didn't take the neighbor's kind .

The next morning, he went to herd and found sheep lost. "The wolf had done it again!" The shepherd was very angry. But this time, he regretted not taking neighbor's advice and not taking action in time. He mended the hole soon, and made the whole sheepfold than before. From then on, his sheep didn't get stolen any more.

The shepherd was smart to prevent sheep from being stolen by mending the hole of the sheepfold. What would you do you made a mistake or did something wrong? Do something to make it up, just as the saying goes, "Better late than never!"