The guzheng is a traditional Chinese musical instrument. It belongs to the zither（齐特琴）family of string instruments. It is the parent of many musical instruments of some other countries.

    The guzheng should not be confused with the guqin, another ancient Chinese zither but without bridges. Now the guzheng is zither with movable bridges and usually 21 strings, although it can have from 15-25 strings. The guzheng's strings were formerly made of silk, though most players used metal strings by the 20^th century. Since the mid-20^th century most performers use steel strings. The guzheng has a large resonant cavity（共振腔）.

    The guzheng has existed since the Warring States Period and became especially popular during the Qin dynasty. The number of strings on the guzheng has always fluctuated. There were as few as 6 to as many as 23 strings during the Tang dynasty. The earliest record of the guzheng belonged to the historian Sima Qian. Until 1961, the common guzheng had 16 strings, although by the mid-20^th century 18-string guzheng were also in use. In 1961, Xu Zhenggao, together with Wang Xunzhi, introduced the first 21-string guzheng after two years of research and development. In 1960, they also invented the “S-shaped” left string rest, which was quickly adopted by all guzheng makers and is still used today. This curve allows for greater ease in tuning the strings and, combined with strings of different thickness, allows for greater resonance in both the deeper and the higher pitch（音调）ranges. The 21-string guzheng is the most commonly used one, but some traditional musicians still use the 16-string one.

    While I was waiting to enter university, I saw in a newspaper a teaching job1at a school about ten miles from where I lived. Being very short of2and wanting to do something3I applied (申请),4as I did so, that without a degree and with no5of teaching my chances of getting the job were6.

    However, three days later, a letter arrived, calling me to Croydon for a meeting with the headmaster. It proved to be a7journey: a train to Croydon station, a ten-minute bus ride and then a walk of at8a quarter of a mile. As a result I arrived there, feeling too hot to be nervous. It was clearly the9himself that10the door. He was short and round.

    "The school," he said, "is made up of one11of twenty-four boys between seven and thirteen." I should have to teach all the subjects except art,12he taught himself. I should have to divide the class into13groups and teach them in turn at three different14 and I was15at the thought of teaching maths—a subject at which I wasn't very16at school. Worse perhaps was the idea of17to teach them on Saturday afternoon because most of my friends would be18themselves at that time.

    Before I had time to ask about my salary, he got up to his19 "Now" he said, you'd better meet my wife. She is the one who really20this school.

    Unsurprisingly, people who are very busy also tend to be very successful and knowledgeable, so it's in your interest to befriend with them. But how do you talk to such busy people in order to make friends with them?{#blank#}1{#/blank#} the same rules apply. However, there are a few specific rules for talking with busy people in particular.

    Remember that even busy people are social creatures. That people are busy doesn't mean they don't want to chat with others or they don't enjoy it.{#blank#}2{#/blank#} Busy people can be very social and friendly. Like anyone else, they have a deep-seated need to socialize and make friends.

    {#blank#}3{#/blank#} They know they're capable and in demand, but it doesn't mean they expect others to prove themselves to them. The best use of your time talking with busy people is not in trying to impress them. Focus on making a conversation and creating a connection, not on proving yourself.

    Spend more time in their field. When dealing with busy people, since their time is in high demand, your favorite topics take a slight backseat to theirs. It usually makes sense to make sure they find the topics you talk about meaningful.{#blank#}4{#/blank#}

    Get to the point.{#blank#}5{#/blank#}Their time is highly valuable. So they don't need you to sugar coat your messages that much, they just want you to say what you have to say.

A. Don't try to prove yourself.

B. Don't hesitate to change your plans.

C. They just don't have that much time for it.

D. It's comfortable for them to chat with people who they like.

E. Mostly, talking to busy people is the same as talking to any others.

F. Once you've found a topic they enjoy talking about, you should explore that topic.

G. Busy people have little patience for communicators who beat around the bush.

    “I never wanted to come on this stupid hiking trip!” Jeff's voice was panicked. His father stopped and turned to look at the boy.

    “This is hard on you, son. But you've got to come through with your courage.”

    “But I am scared!” Jeff shouted.

    “Please have enough love for your brother to think this through!” His father replied, “We just don't have the time to stop. And I don't know if I can make it without stopping every so often. While you're only ten, you're strong and fast. Do you remember the way back from here to the road, if you had to go alone?”

    Jeff flashed back to the painful scene of his seventeen-year-old brother Mark at their campsite. He'd been bitten by a snake during a rough hike. He needed medical attention right away. Worse still, their cell phone was dead.

    “Jeff? Could you make it to Flint without me? You can get help there.”

    Jeff nodded, said goodbye to his father and continued climbing over the rocks. The rocks and branches threatened his footing and speed, but stone by stone, he made his way up the valley.

    Jeff turned and made the final climbing-up toward the road. When he reached it, he rested himself, breathless. “Can't stop,” he thought. “Mark's in big trouble Keep going.” Just as he pulled himself upright, a truck sped by, heading for Flint " Hey!” he shouted excitedly, waving both arms. The truck stopped, "Jump in, boy! What's up? "The driver asked, Jeff got in and explained. Immediately the driver reached for his cell phone. “Help! Help! Better get the helicopter in there,” he seemed to be shouting into his hand. But Jeff wasn't sure about that because everything got unclear and then went black and quiet.

    Hours later, Jeff opened his eyes to find himself in a hospital, with his father nearby. His father told him that the helicopter airlifted Mark to the hospital and he would be fine in a few days. His father hiked himself out of that valley and took a ride from someone to the town. “You're a hero, son,” his father finally said with a smile.“ You saved Mark.”

    “I never wanted to come on this stupid hiking trip!” Jeff's voice was panicked. His father stopped and turned to look at the boy.

    “This is hard on you, son. But you've got to come through with your courage.”

    “But I am scared!” Jeff shouted.

    “Please have enough love for your brother to think this through!” His father replied, “We just don't have the time to stop. And I don't know if I can make it without stopping every so often. While you're only ten, you're strong and fast. Do you remember the way back from here to the road, if you had to go alone?”

    Jeff flashed back to the painful scene of his seventeen-year-old brother Mark at their campsite. He'd been bitten by a snake during a rough hike. He needed medical attention right away. Worse still, their cell phone was dead.

    “Jeff? Could you make it to Flint without me? You can get help there.”

    Jeff nodded, said goodbye to his father and continued climbing over the rocks. The rocks and branches threatened his footing and speed, but stone by stone, he made his way up the valley.

    Jeff turned and made the final climbing-up toward the road. When he reached it, he rested himself, breathless. “Can't stop,” he thought. “Mark's in big trouble Keep going.” Just as he pulled himself upright, a truck sped by, heading for Flint " Hey!” he shouted excitedly, waving both arms. The truck stopped, "Jump in, boy! What's up? "The driver asked, Jeff got in and explained. Immediately the driver reached for his cell phone. “Help! Help! Better get the helicopter in there,” he seemed to be shouting into his hand. But Jeff wasn't sure about that because everything got unclear and then went black and quiet.

    Hours later, Jeff opened his eyes to find himself in a hospital, with his father nearby. His father told him that the helicopter airlifted Mark to the hospital and he would be fine in a few days. His father hiked himself out of that valley and took a ride from someone to the town. “You're a hero, son,” his father finally said with a smile.“ You saved Mark.”

    This year's flu season is pretty scary. To try to minimize the effects, public officials are still urging anyone who hasn't yet gotten their flu shot to get one as soon as possible. However, even if every single person got a shot in the arm, the vaccine(疫苗)--- with its excellent 36 percent effectiveness---would not prevent everyone from getting infected with the annoying virus. Knowledge is power, so here's what goes on in your body when you come down with the flu.

    The influenza virus primarily attacks your nose, throat, and the tubes that lead to your lungs. But the flu is so much more than that. Your muscles ache, your head hurts, and your appetite goes down, among other things. To our surprise, almost all of these symptoms have less to do with the virus itself than with your immune(免疫的)response to them. Unfortunately, the very defense you have in place to ge rid of the flu is the reason you feel so painful when you recover.

    The virus usually enters through your mouth, typically by way of your hands. But it takes a few days for symptoms to set in. While this process might cause some harm to your nose and throat, it's nothing major, and nothing like the symptoms that typically accompany a bad or even mild case of the flu.

    The real fun starts when your immune system begins to fight. Your immune system comes in two parts: the innate system and the adaptive. The innate immune system is essentially an all-purpose tool. As soon as your body senses the presence of any injury or invader (入侵者), the innate immune system launches into action by producing tiny proteins called cytokines and chemokines. The cytokines reproduce almost immediately and start to attack the virus. This increase in immune cells creates an serious inflammation(炎症) throughout the body. But the worst is still to come. Meanwhile, the chemokines work with the adaptive immune system to help create T cells. These cells are a special type of white blood cell that works in a much more specific way: They find the influenza virus, identify what's special about it, and create something unique on their surface that finds and destroys similar invaders.