—What a pity！Stella _______ here to see you.

注意：1. 短文须包括所有内容要点，可适当发挥。2. 词数：150左右。开头和结尾已给出，不计入总词数。

Dear Mom and Dad,

    The annual college entrance examination is around the corner. On this special occasion, how I wish I could have a heart-to-heart talk with you.

    I am quite confident of my future life and I do wish you good health and a happy life.

Yours ever,

Li Xiang

    Kunta wondered why the white people had done this to him. Born a free man, he was now in chains. Heavy iron chains around his feet and hands were fixed to a metal bar that ran round the hall about ten centimeters off the ground. He was just able to lie down on the ground, but could not stand up.

    Kunta had been seized in the forest and then hit on the head with a hard object. When he woke up, his hands and feet had already been tied together. What shocked him most was that the men who carried him were black. He reasoned with them, and tried to persuade them to set him free. But they would not listen to him. When they came to the river, a white man was waiting in the boat for them. There was an argument about money, so it seemed, in a language that Kunta did not understand. Finally, Kunta was thrown into the bottom of the boat and covered with an old smelly cloth. The men took him in their boat to the castle on the coast where he was now held prisoner.

    Another thing which shocked Kunta was that women were held in the castle too. He could hear their crying, also children's voices. What was to become of them all, he wondered. For all his life, he had known that people suddenly disappeared from their villages. He had known that it was not safe to travel alone in the forest near the coast. But why did white people want to catch Africans and put them in chains? Would they be killed or even eaten? The situation seemed hopeless and he knew his life was in danger.

    Worse was to come. A few days later about 140 black people were taken and put on a tall sailing ship waiting off the coast. Once on the boat, they were taken below and their chains were fixed to two bars that ran the length of the ship. Their feet were fixed to one bar and their hands to another bar. Thus they lay on hard wooden boards, unable to stand up or move around.

    The sea journey lasted over sixty days and nights. They had rough weather and Kunta's back bled from rolling over on the hard wooden boards. Many of the men fell sick with fever. They sighed and cried out for more water, but food and water were only given out once a day. Once in a while sailors came down, Kunta thought, to carry sick men upstairs for treatment. When the ship finally arrived in a port, the wooden cover was opened wide and Kunta could see in daylight for the first time across the part of the ship where he had been chained. About a third of the people who had been chained up below at the beginning of the journey were missing.

—Don't worry. I will try to improve it.

    Try this: For an entire day, forget about the clock. Eat when you're hungry and sleep when you're tired. What do you think will happen?

    You may be surprised to find that your day is much like most other days. You'll probably get hungry when you normally eat and tired when you normally sleep. Even though you don't know what time it is, your body does.

    These patterns of daily life are called circadian rhythms, and they are more than just habits. Inside our bodies are several clocklike systems that follow a roughly 24-hour cycle. Throughout the day and night, our internal clocks direct changes in temperature, body chemicals, hunger, sleepiness and more.

    Everyone's rhythms are unique, which is why you might like to stay up late while your sister always wants to go to bed early. But overall, everyone is programmed to feel tired at night and energetic during the day.

    Scientists have known for a long time that the light of day and the dark of night play important roles in setting our internal（内部的） clocks. Now, new discoveries are giving scientists insights into how these clocks work.

    Learning about our body clocks may help scientists understand why problems arise when we act out of step with our circadian rhythms. For example, traveling across time zones can make people wake up in the middle of the night. Regularly staying up late can make kids do worse on tests and quizzes. And working shifts at night leads to higher rates of heart disease, diabetes and obesity.

    “There is a growing sense that when we eat and when we sleep are important parts of how healthy we are,” says Steven Shea, Director of the Sleep Disorders Research Program at Brigham and Women's Hospital in Boston.

    Scientists still aren't sure why the timing of sleep matters so much, Shea says. But research findings suggest that our circadian rhythms are more important than we give them credit for.

    “During the night, we are prepared to sleep,” Shea says. “During the day, we are prepared to eat and move around. If you reverse (颠倒)what you are doing, everything is out of phase. That can have unfavorable consequences.”