Central Idea Practice *UPDATE*

Group 1

• Global warming is a topic that has been causing a lot of arguments lately.
• Some scientists say that temperatures around the globe have been rising because of all the pollution humans have let into the air.
• Others say that temperatures around the globe naturally rise every few thousand years.
• They say that it is not the fault of humans at all.
• People cannot seem to agree on the cause.
• Whatever the case, however, rising temperatures are causing glaciers around the world to melt.
• The lives of plants and animals are in danger.
• Effects of rising temperatures are being felt around the world.
• Whether everyone agrees about the causes or not, everyone is going to have to deal with the effects.

Group 2

• Flush toilets were first used in India and Pakistan over 2,700 years ago.
• There were also toilets in ancient Egypt and China.
• In the Roman Empire, toilets were part of some public bathhouses for men and women.
• Then, in 1775, Alexander Cummings invented part of the flush toilet called the S-trap.
• This part used standing water to seal the outlet of the bowl.
• This kept the smell from the sewer from escaping.
• The S-trap is still used today.

Group 3

• An assistance dog is a dog trained to help a person with a disability.
• The dog helps that person get around in daily life.
• Many of these dogs are trained by special organizations.
• Others are trained by professional trainers and their owners.
• There are three kinds of assistance dogs.
• The first, guide dogs, help the blind.
• The second are hearing dogs. They help people who are deaf or hard of hearing.
• The last group is a service dog. Service dogs help with people who cannot use their arms or legs.

Group 4

• Mad Cow Disease has received a lot of news attention lately.
• It is a brain disease in cattle.
• It causes odd behavior, difficulty walking, and eventually death.
• Scientists believe this disease came about recently.
• It comes from feeding cattle extra vitamins that have parts from sick sheep.

Group 5

• All living things are born, grow during their lifetime, and eventually die.
• Tadpoles are born, grow, change into frogs, and eventually die.
• Chicks are born, grow to be adult chickens, and eventually die.
• What would happen if no new chickens were born to replace those that died?
• There would be no more chickens in the world—they'd be extinct.
• In order to keep themselves from dying out, all living things must reproduce themselves.

Group 6

• Hummingbirds will entertain for food.
• They will put on an aerial show by soaring, diving, then hovering in midair before retreating temporarily to nearby trees and shrubs.
• Other tiny performers perch in nearby trees and shrubs or sip nectar from flowers while waiting their turn to go onstage.
• Several years ago we thought it would be nice to invite a few hummingbirds to our backyard.
• We put up a feeder and a few birds showed up for dinner.
• Little did we know they would invite all their friends.
• More of the feisty little birds show up each year.
• The birds earn their keep by entertaining us and our guests.
• Children and adults love to see their shows.
• The aerobatics start early each morning and continue until nightfall, so the entertainment is available most any time of the day.

Group 7

• Compliments ought to be specific.
• The best ones don't just say what you like, they say why you like whatever it is that you like.
• If you compliment someone on a new dress, don't just say, "I like that dress."
• Instead, you could say, "I like that dress. The red and green gargoyles and the purple stripes bring out the yellow in your eyes."
• It's a much more specific compliment than "That's a pretty dress."

Group 8

• The Great Depression caused many problems for Americans.
• Businesses were not doing well, and many people were out of work.
• The stock market crashed in 1929 and did not come back up until 1933.
• Thousands of banks failed.
• Many people who had money in banks lost some or all of it when their banks failed.

Group 9

• Number One Observatory Circle is the home of the U.S. vice president.
• The house is located on land for the U.S. Naval Observatory.
• The home was built in 1893.
• It was first the home for the head of the observatory.
• In 1923, it became the home for the Chief of Naval Operations.
• Congress made it the vice president's home in 1974.
• Before this, the vice president lived in his own home.
• The first vice president to live in the home full time was Walter Mondale.
• He was Vice President to Jimmy Carter.

Group 10

• On October 11, 1910, Theodore Roosevelt became the first president to fly in a plane.
• The flight took place after Roosevelt's last term as president.
• The plane had been built by the Wright brothers.
• The plane was flown by Arch Huxley for about four minutes.
• Roosevelt and Huxley took off from Kinloch Field in St. Louis, Missouri.
• Today, that field is home to that city's major airport.

Group 11

• Most people think that Johann Sebastian Bach played the piano, but this is not true.
• The piano was not invented until just two years before he died.
• Bach's main instrument was the organ.
• He was a great organist.
• He wrote a lot of wonderful music for that instrument.
• He also played other keyboard instruments that were ancestors of the piano.
• Among these instruments was the harpsichord.
• Along with Mozart, Bach is considered to be one of the all-time great composers.

Group 12

• Some people think that English is a hard language to learn, but experts disagree.
• They say that no human language is more or less difficult than any other.
• All babies learn to speak the language of their parents very quickly.
• Most babies learn to walk by the time they are a year old.
• They learn that it's easier for them to get what they want if they can speak.
• A baby born to parents who speak English will learn English as quickly as a Japanese child whose parents speak Japanese.
• Of course, experts agree that learning a second language can be much harder.

Group 13

• The idea of human rights is the belief that everyone should have certain rights.
• They are entitled to these rights just because they are human.
• The idea is not a new one.
• It has been developing since the beginning of man's history.
• A strong commitment to human rights is considered a good measure of a country's potential for being a good neighbor and contributing to world peace.
• The use of threats and violence is an indication that a government cannot be trusted and may be a threat to world peace.
• In 1948 the United Nations adopted the Universal Declaration of Human Rights.
• The declaration lists the rights that individuals should have.
• One of those rights is the right to take part in government.
• Others have to do with working and living conditions.

Group 14

• Stingrays are fish, closely related to sharks.
• They can be found in salt water oceans and seas throughout the world.
• There are some freshwater species in Asia, Africa, and Florida.
• Stingrays swim with a "flying" motion.
• Instead of fins, they have wings on their sides.
• The wings' movement allows the stingrays to "fly" through the water.
• Their stinger is a spine that grows from the tail.
• It can grow to be over 14 inches long.
• The spine is poisonous.

Group 15

• We often let others know what we are thinking without using words.
• The name that we give for this kind of communication is body language.
• Body language includes gestures, facial expressions, and posture.
• Body language does not always mean the same thing to everyone.

Group 16

• The Nobel Prize for Literature went to Doris Lessing of Britain.
• She won for her book The Golden Notebook, which was written in 1962.
• Lessing has been named a candidate for the award for 30 years.
• She once said, "I'll never get it."
• Less than two months after her 88th birthday, she received her award.
• She was the oldest person to win this prize.
• Lessing was honored at the Nobel Prize ceremony in Stockholm, Sweden in December.

Group 17

• In the early 1800s, boats, canals, and trains made it easier to head west.
• After the War of 1812, thousands of Americans moved beyond the Appalachians.
• The Appalachians are not as tall as the Rockies.
• More and more people came from Europe, too.
• Some of these people had been poor and hungry in their old countries.
• In America, they hoped to find land to farm.
• They wanted the chance for a better life.

Group 18

• Nutrias are causing major problems in Louisiana.
• Someone brought the rodents to the state 40 years ago, hoping to make a fortune from the furs.
• Nobody wanted to buy the furs, and now the animals roam freely.
• They're destroying the wetlands.
• They eat the roots of the water plants along the canals.
• The plants die, and the banks of the canals begin to erode.
• The animals are costing the state millions of dollars, and no one seems to know what to do with them.