【正文】 ial reanization. Later, Napoleon, the ruler of France, spread the change to the rest of the continental Europe. He did this because he was lefthanded himself, and he wanted his armies to march on the right so that he could keep his left arm between himself and any enemy. From then on, any part of the world which became part of the British Empire marched on the left, and any part controlled by the French marched on the right. After the American Revolutionary War (17751783), the US became independent and decided to make traffic drive on the right in order to cut its ties with Britain. Once America became the center of the car industry, if you wanted a good car, you bought an Americanmade righthand drive vehicles. From then on many countries changed out of necessity. Today, the EU would like Britain to be the same as the rest of Europe, but this is no longer possible. It would cost billions of pounds to change everything round. The last European country to convert to driving on the right was Sweden in 1967, but there were far fewer cars there, and the population was much smaller. 21. Why did people travel on the left before the late 18th century? A. They could be safer from attacks. B. The government required them to do so. C. There were more lefthanded people back then. D. They could prevent strangers passing by their left side. 22. What was Napoleon’ s attitude to walking on the left? A. Negative. B. Indifferent. C. Supportive. D. Uncertain. 23. For Americans, driving on the right was a way to show . A. the connection with France was broken B. the American Revolutionary War had ended C. America was the center of the car industry D. the US was no longer controlled by the UK 24. The underlined phrase “ convert to” in the last paragraph means . A. insist on B. give up C. change into D. disagree with B A solar bag is a long plastic bag made from very thin plastic and colored black to take in solar energy. The heated air inside the bag causes the bag to float. Although the solar bag looks similar to a regular black trash bag, the key difference is the thickness of the plastic. A great science experiment might be testing bags of different thicknesses to see which one floats the highest! Materials ? Solar bag ? Solar bag string Notice that the bag is made out of a lightweight plastic material. Be careful when dealing with the bag since the plastic will tear easily. Carefully take the plastic bag from the packaging and hold one of the open end of the bag. Tie this end with string. The best time for a launch is in the cool morning. We have not had much success with a launch in the middle of a hot day. Choose a proper place for the launch. Find a field clear of any buildings, trees and power lines. Choose a day to do the experiment when it is sunny and free of any wind. Put the solar bag onto a soft surface like grass. Have one person hold the bag open as you begin to run around and fill the bag with air. Fill the bag with air until about 2 feet remains without air so that you can hold it in your hand. Close the end and use a string to keep it on the ground. The last part of the work is done by the sun. Gather around the giant bag but try not to touch it— sharp fingernails will easily break the thin plastic. Be careful! The outside of the bag also gets very hot to the touch. It’ s important to remember that it may take as long as ten minutes for the air inside to heat up enough to cause the bag to float. 25. What’ s the difference between a Solar Bag and a regular black trash bag? A. The weight. B. The thickness. C. The material. D. The color. 26. The best time to launch a Solar Bag is in . A. a sunny cool morning without any wind B. a sunny hot afternoon without any wind C. a sunny cool morning with some wind D. a sunny hot afternoon with some wind 27. A good place for a launch is . A. between buildings B. in an open area C. on top of a tree D. near a power station C Anna Schiferl hadn’t even got out of bed when she reached for her cell phone and typed a text to her mum, one recent Saturday. Mom was right downstairs in the kitchen. The text? Anna wanted an egg for breakfast. Soon after, Joanna Schiferl called, “ If you want to talk to me, Anna, e downstairs and see me?” Anna laughs about it now. “I was kind of being lazy,” she admits. These days, many people with cell phones prefer texting to a phone call. And that’s creating a munication divide — the talker vs. the texters. Some would argue that it’s no big deal. But many experts say the most successful municators will, of course, have the petence to do both. And they fear that more of us are unable to have — or at least are avoiding — the traditional facetoface conversations. Many professors say it is not mon to see students outside of class. “I sit in my office hours lonely now because if my students have a question, they me, often late at night,” says Rence Hosuton, a professor at the University of Puget Sound in Washington state. “And they never call.” As Ann