Harmful microbes (微生物) like bacteria (细菌), viruses (病毒) and other germs (病菌) are pathogens (病原体). They may enter your bodies and make you ill. The immune system (免疫系统) is the body’s defence (防卫) 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 (细胞), grouped into phagocytes (噬菌细胞) and lymphocytes (淋巴细胞). Phagocytes are a type of white blood cell. They are swimming around in your blood stream, always on the lookout for antigens (抗原) —the pathogens that have entered your bodies. Whenever they see one, they 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 and if they see the same antigen again, they quickly recognize (识别) 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 (白血病), then genetically changed them into “serial killer” cells to attack cancer cells. The study was small but the results were ground-breaking. 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, will help you achieve it.
1.The immune system can _________.
A. keep you from antibodies. B. protect you against antigens.
C. make your bodies weak and sick. D. help microbes enter your bodies.
2.How are the sneaky antigens found and killed
A. B cells produce antibodies to tell T helper and T killer cells.
B. B cells create “memory cells” to swim around in the blood.
C. Skin, tears, acidic juice and immune cells work together.
D. Phagocytes, B cells, T helper and T killer cells work together.
3.After a B cell or a T cell attacks an antigen, they create _________.
A. phagocytes B. lymphocytes C. memory cells D. serial killer
4.The underlined word “it” in the last paragraph refers to _________.
A. Less antigens can be killed by the immune system
B. The immune system can be changed into the “serial killer”
C. White blood cells act less quickly in the immune system
D. The immune system can be made more powerful
5.This article is mainly about _________.
A. the types of white blood cells B. an introduction to the immune system
C. a research report about human health D. the cause of illness and disease
“Mom, I made a new friend at school today. Can she come over tomorrow?” asked Donna, my 10-year-old daughter. Donna was very shy and I wanted her to make some friends to bring her out of her shell.
“Sure, honey, that sounds great.” I said, thinking back to my own best friend, Lillian. We lived across the street from each other in Washington Heights, New York. We met at the age of 10, too. Like my daughter, I was shy, but Lillian drew me out. She was one of the friendliest people in school, with shiny black hair and a mile-wide smile. I knew we would be best friends forever.
In senior high school, Lillian went on a trip to Florida. This was the first time we had to be away from each other for a few days. “I’ll be back soon.” she told me. But three days later, Lillian’s sister told me that she had fallen into a river and hadn’t come out any more. Soon, my family moved to New Jersey. Whenever I thought of her, tears came into my eyes.
The next day Donna brought her new friend home. “Hi, Mrs. Loggia.” the little girl said. Her hair was so shiny and black and she shot me a big smile. “My name is Laura.”
My daughter’s new friend was so much like Lillian. I was still puzzled (迷惑) when Laura’s mom came to pick her up later that afternoon. I opened the door to let her in. “Judy!” she cried. “It’s me, Lillian’s sister, from Washington Heights.” Yes, my daughter’s friend looked familiar. She was Lillian’s niece.
1.Who would come to the writer’s house?
A. Lillian. B. Laura C. Donna.
2.The underlined words in the first paragraph “to bring her out of her shell” mean _________.
A. to help her become smart B. to help her walk out of her house
C. to help her become less shy
3.Laura looked familiar to the writer because she _________.
A. had shiny black hair and a big smile, too B. was from Washington Heights
C. was Lillian’s niece
4.Why did the writer lose her best friend? Because _________.
A. her best friend lost her life on a trip B. she moved to New Jersey
C. her best friend travelled to Florida
5.We can infer (推断) from the passage that _________.
A. Laura is a shy girl B. Laura is outgoing
C. Laura and Donna are of the same age
Do you know how a young dog or cat gets to know a new home? The animal uses its nose. Right away it smells its new places. Then it makes wider and wider circles, smelling all the time. Before long it can find its way home very well, even in the dark. It simply follows something it knows well.
Stories happen about animals who found their way across land they had never smelled before. Take the case of Smoky, a small white cat. Smoky had some funny red hair around its right ear. One day Smoky and his owner began a long journey. They were moving from Oklahoma to Tennessee. When they were just eighteen miles from their Oklahoma home, Smoky jumped out of the car. Then he found his way back to the old house. There he wandered around outside for many days. Finally he disappeared.
A year later Smoky meowed at the door of a house in Tennessee. A man opened the door. “Is that you, Smoky?” he said in surprise. At first he couldn’t believe it. Then he saw the red hair around its right ear. It was Smoky!
1.What is the first thing a pet does in a new place?
A. It smells the new place. B. It finds its way in the dark
C. It follows something it knows.
2.Put these events in the right order that they happened.
①Smoky got to Tennessee. ②Smoky jumped out of the car. ③Smoky went to his old house.
A. ③①② B. ②③① C. ①③②
3.The underlined word “wandered” in the passage means _________.
A. 思考 B. 围绕 C. 游荡
4.How long did Smoky take to get to the house in Tennessee?
A. A year. B. A month. C. A week.
5.What is the best title of the passage?
A. An Excellent Memory B. A Surprising Journey C. A Humorous Cat
Letting kids learn more about science at an early age is easier than you think. It is happening all around us, and you can ______ everyday things to encourage your children’s interest.
Most parents believe it is difficult to help their children with science. But you don’t need a high scientific degree to teach your children science. All you need is that you’re willing to try, to see the world, and to _____ the time to encourage their natural curiosity (好奇).
You can help by having an active attitude (态度) towards science yourself. Then start ______ by asking your children questions about the things you see every day. And then listen to their answers without judging (评判) them, which will ______ their confidence (自信), and help you decide just what your children know or do not know.
Different kids have different interest, so they need different kinds of science projects. Collecting rocks may interest your young daughter, but your older son may need something more to deal with it. Knowing your children is the best way to ______ enjoyable learning activities. Here are some more pieces of advice:
Choose activities that are the right ______ of difficulty. If you are not sure, pick something easier.
Read the suggested ages on any projects, books, and then make sure that the activity is ______ for your child.
Let your child choose the project or activity himself. It’s easy enough to ask rather than force him. Suggest choosing 2 or 3 things your child can do. When a child picks something he is ______ in, he will enjoy it and learn more from it.
1.A. buy B. use C. make D. invent
2.A. take B. solve C. follow D. raise
3.A. seriously B. cheaply C. simply D. completely
4.A. lose B. create C. believe D. improve
5.A. take B. find C. cancel D. print
6.A. point B. way C. answer D. level
7.A. proper B. deep C. famous D. cheap
8.A. known B. interested C. proud D. good
A
Jim is a famous English teacher now. But he said he was not a good ______ when he was young. He was often late for class and didn’t like doing his homework. Sometimes he slept in class while the teacher was teaching. He didn’t understand much, ______ he always thought he understood everything. One day the teacher asked the students a question, “When Mary was ten years old, ______ brother Bob was twenty. Mary is fifteen now and how old is her brother Bob?” Jim said, “That’s easy. Bob is twice as ______ as Mary, so he is now thirty.”
Another time, the teacher in a science class asked, “When it thunders, ______ do we always see the light before we ______ the sound?”
“But, Miss,” said Jim quickly, “don’t you ______ our eyes are in front of our ears?”
1.A. teacher B. farmer C. student
2.A. but B. and C. or
3.A. your B. her C. his
4.A. old B. young C. tall
5.A. what B. when C. why
6.A. see B. hear C. smell
7.A. hope B. read C. know
﹣Who is Dave looking _________?
﹣His mother. She’s been in hospital for a few days.
A. for B. at C. after
