The human body has hundreds of muscles. The three types are skeletal muscles, smooth muscles and cardiac, or heart muscles. Each kind of muscle has a special job to do. The skeletal muscles are attached to the bones; they actually hold the skeleton together. Strong cords, called tendons , help connect these muscles to the bones. Skeletal muscles give us strength and allow us to move in many ways. If you look at skeletal muscles through a microscope, you will see that it has bands of fibers that look like stripes . These stripes are called striations. Skeletal muscles usually move because the brain has sent a conscious message to them telling them what to do. This is called voluntary movement. Another type of muscle is smooth muscle. Unlike skeletal muscle, smooth muscle does not have striations. This is found in organs such as the stomach, the bladder , the lungs and the eyes. Smooth muscles are smaller than the skeletal muscles and they move involuntarily. The brain tells these muscles what to do, but we aren't even aware of it. For example, we don't have to think about breathing or digesting food. The smooth muscles just do their jobs automatically. For this reason smooth muscles are sometimes called involuntary muscles. Like smooth muscle, cardiac muscle also works involuntarily. It is a very thick muscle that is found only in the walls of the heart. Its job is to pump blood out of the heart and into blood vessels called arteries . The arteries help carry the blood to all parts of the body. When the cardiac muscles relax, they let blood back into the heart. Cardiac muscles have striations, just like skeletal muscles do. When we _ , the job is done by smooth muscles. A) close our eyes B) kick a ball C) hug our friends D) lift a suitcase
A

Robert Spring, a 19th century forger , was as good at his profession that he was able to make his living for 15 years by selling false signatures of famous Americans. Spring was born in England in 1813 and arrived in Philadelphia in 1858 to open a bookstore. At first he make some money by selling his small but genuine of early U.S. autographs . Discovering his ability at copying handwriting, he began imitating signatures of George Washington and Ban Franklin and writing them on the title pages of old books. To make less the chance of detection , he sent his forgeries to England and Canada for sale and circulation . Forgers have a hard time selling their products. A forger can't approach a respectable buyer but must deal with people who don't have much knowledge in the field. Forgers have many ways to make their work look real. For example, they buy old books to use the aged paper of the title page, and they can treat paper and ink with chemicals. In Spring's time, right after the Civil War, Britain was still fond of the Southern states, so Spring invented a respectable maiden lady known as Miss Fanny Jackson, the only daughter of General "Stonewall" Jackson. For several years Miss Fanny's economic problems forced her to sell a great number of letters and manuscripts belonging to her famous father. Spring had to work very hard to satisfy the demand. All this activity did not prevent Spring from dying in poverty, leaving sharp-eye experts the difficult task of separating this forgeries from the originals. Robert Spring spent 15 years _ . A) running a bookstore in Philadelphia B) corresponding with Miss Fanny Jackson C) as a forger D) as a respectable dealer
C

Although English is not as 0old as Chinese it is spoken by many people around the world every day. English speakers are always creating new words, and we should be able to know where most words come from. Sometimes, however, no one may really know where a word comes from. Did you ever think about why hamburgers are called hamburgers, especially when they are not made with ham ? About a hundred years ago, some men went to America from Europe. They came from a big city in Germany called Hamburg. They did not speak good English. But they ate good food. When some Americans saw them eating round pieces of beef ,they asked the Germans what it was. The Germans did not understand the question and answered, "We came from Hamburg." One of these Americans owned a restaurant, and had an idea. He cooked some round pieces of beef like what the men from Hamburger ate. Then he put them between two pieces of bread and started selling them. Today "hamburgers" are sold in many countries around the world. Whether this story is true or not, it certainly is interesting. Knowing why any word has a certain meaning is interesting, too. The reason may be found in any large English dictionary. According to the story, the word "hamburgers" comes from _ . A) China because it has a long history. B) England because Germans don't speak good English. C) The round pieces of beef those people from Hamburg brought to America. D) English speakers because they always create new words.
C

SALT LAKE CITY, March 1, 2010 --- Like silkworm moths , butterflies and spiders, caddisfly larvae spin silk, but they do so underwater instead of on dry land. Now, University of Utah researchers have discovered why the fly's silk is sticky when wet and how that may make it valuable as an adhesive tape during an operation. "Silk from caddisfly larvae may be useful some day as a medical adhesive for sticking wet tissues," says Russell Stewart, an associate professor of bioengineering and principal author of a new study of the fly silk's chemical and structural properties. "I picture it as sort of a wet Band-Aid, maybe used inside in operations --- like using a piece of tape to close a cut," he adds. "Gluing things together underwater is not easy. Have you ever tried to put a Band-Aid on in the shower? This insect has been doing this for 150 million to 200 million years." There are thousands of caddisfly species worldwide. Some species spend their larval stages developing underwater, and build an inch-long, tube-shaped case or shelter around themselves using sticky silk and grains of rock or sand. Other species use silk, small sticks and pieces of leaves. Each larva has a head and four legs that stick out from the tube.The larval case gets wider as the larva grows.A caddisfly larva eventually pupates as it develops into an adult fly and then hatches. Caddisflies now live around the world in waters ranging from fast streams to quiet low lying wet land. The caddisflies'adaptation to diverse habitats is largely due to the inventive use by their larva of underwater silk to build complex structures for protection and food gathering. Caddisflies fall into two groups. Some build their case and then drag it along with them underwater as they search for food. Some build a shelter glued to a rock,with a silk net to catch passing food. The passage is most probably a _ . A) science fiction novel B) science news report C) biography of researchers D) social affairs report
B