Let's try doing the following experiment.

 What to do：

 Use string to hang a paper clip or other small object at about chest（胸部）level.

 Pick up a stick，such as a broom handle. Take three or four steps away from the paper clip.

Now close one eye and walk toward the paper clip. Try to touch it with the tip of the stick. If you miss，try again，still keeping one eye closed. Now try it with both eyes open and see if it's easier to do.

 How it works：

 In the experiment，you have to judge how far away the paper clip is. Your brain has several ways of doing this.

 One simple way depends on how much your eye has to focus（聚焦）itself. Using only one eye，most people will find it difficult to touch the paper clip on the first try，but the brain still gets some information about distance—though not much.

 Your brain can judge distance much better when you look at something with both eyes. In fact，your brain has more than one way to use both eyes in judging distance. For example，to see anything clearly，you have to make both of your eyes point at the object. When you look at a nearby object，your eyes turn inward. You can feel this happening if you look at the tip of your finger and move your finger toward your nose.

 Your brain gets information from the eyes about how much they are pointing toward each other. Using that information，the brain can tell how far away any object is，whether it is a basketball or a paper clip.

    Harmful microbes like bacterias, viruses and other germs are pathogens. They may enter your bodies and make you ill. The immune system is the body's defence system that protects you from illness and disease caused by the pathogens.

    The immune system is made up of non﹣specialized defences such as skin, tears and the acidic juice produced by the stomach, keeping you from the pathogens. It also has some highly specialized defences, which are different kinds of immune cells, grouped into phagocytes and lymphocytes. Phagocytes are a type of white blood cell. They are swimming around in your blood stream, always on the lookout for antigens﹣the pathogens that have entered your bodies. Whenever they see one, their will eat it. However, some antigens are hard to find and kill. Then lymphocytes, which are also white blood cells and the main types are B cells, T helper cells and T killer cells, Will be the killers of the sneaky antigens.

    B cells, T helper and T killer cells work together to find and kill these antigens. B cells produce substances, called antibodies, which stick to the antigen. When that happens, it will tell the T helper cells to come over and either: 1. help the B cells kill the antigen, or 2. call the phagocytes or T killer cells to move in for the kill. Once a B cell or a T cell attacks an antigen, they create cells to "remember" it. Those "memory cells" hang out in your blood if they see the same antigen again, they quickly recognize, it so your immune system can act faster at killing it.

    The immune system is more powerful than you probably imagine. Scientists from the University of Pennsylvania recently took immune cells from three patients with leukemia, then genetically changed them into "serial Keller "cells to attack cancer cells. The study was small but the results were groundbreaking. The modified immune cells increased at least 1, 000 times in the body and killed all the cancer cells. Therefore, more "memory cells" were created.

    The immune system can be developed. Eating lean protein food （beef, beans ）and food rich in vitamins A, C, and E（sweet potatoes, carrots ）, taking a 30﹣minute walk every day and reducing your stress levels, etc. will help you achieve it.

    “Without music, life would be a mistake,” famous German philosopher(哲学家) Friendrich Nietzsche said over a century ago. Music is a big part of our lives. But in recent years, some US schools have cut music classes to control budgets(预算).

    For example, Chicago public schools hurt arts education when it fired(解雇)over 1,000 teachers. Among them, 10 percent of the teachers taught art or music, according to The Washington Times. In fact, this is not just a problem in the US. In other countries, such as China and the UK, music classes are not thought to be as important as ones like science, math and history. That's partly because music is not seen as a very important life skill, and it isn't tested. Many students are busy with schoolwork, so parents and students choose to focus on subjects that are tested more often.

    However, learning music is beneficial(有益的)in many ways.

    When playing music, you need different abilities to work together. It is not as simple as it looks, according to Kenneth Guilmartin of Music Together, an early childhood music development program. For example, when playing the piano, people see music notes and decode(解码)them in their brains. They also use their fingers to make sounds. You need to deal with all these things at the same time.

    Music has a special connection with science as well. You can see that many scientists are good at playing music: Einstein played the violin, and German physicist Max Planck was talented in playing the piano.

The 9th day of the 9th lunar month is the traditional Chongyang Festival, which falls on Oct. 4th this year. "Chong" means "double" in Chinese. 1 , as double ninth was pronounced the same as the word to express "forever", Chinese ancestors considered it a good day worth celebration. That's 2 ancient Chinese began to celebrate this festival long ago. 

People follow several customs on Double Ninth Festival. For example, people often 3 the cornel (山茱萸) on their arms or heads because they believe this plant can prevent diseases and avoid disasters. Besides, people like to climb 4 on this day, so Double Ninth Festival is 5 Mountain Climbing Festival. The 9th lunar month often has autumn skies and fresh air. It is a good time 6 sightseeing. When people stand on a high mountain, they will have a good view of a blue sky and dark green mountains, which makes 7 carefree and joyful. Chongyang Cake is also known as "flower cake". It is said that the 8 was originally (最初) prepared after autumn harvest, because farmers wanted to have a 9 of what was just in season. Then gradually it became the cake for people to eat on Double Ninth Festival. Double Ninth Festival is a festival for the 10 . People get together to show their love and concern for their parents and their grandparents. 

Recently, we did a survey about our students' ideas about what kinds of things are the most important in a friend. Here are the {#blank#}1{#/blank#}. 

We found that half of the students think a good friend should have the same hobbies {#blank#}2{#/blank#} they do. Twenty percent hope their friends to be good listeners and can make them {#blank#}3{#/blank#} when they're sad. For another twenty percent, a good friend should be {#blank#}4{#/blank#} talented in something than they are so that these friends can help bring out the best in {#blank#}5{#/blank#}. The rest of the students like good-looking people with cool clothes to be their friends. 

International(国际的) Nurses Day falls on May 12 every year. It is in memory of the birth of Florence Nightingale. Who was this lady?

Nightingale was one of the most important health workers in history. During a war(战争)in the 1850s，she worked with other nurses to care for English soldiers(士兵). She set many important rules for health care. Because of her habit of making rounds(巡诊) at night，people called her "the Lady with the Lamp(灯)". Later in 1860，Nightingale opened a health care school in London. She trained many excellent nurses in this school. 

Every year on this festival for nurses，a special activity is held in London. A lamp is handed from one nurse to another. This means that knowledge is passed from one nurse to another. 

Nurses make up more than half of all health workers，but there are still 5. 9 million more nurses needed in the world. The terrible disease(疾病) has reminded us of the importance of nurses. Without nurses and other health workers，we wouldn't be able to fight against diseases successfully.