1 . Stephen Warren, study leader at the University of Washington, has been on the case of the green icebergs for more than 30 years. He first took samples from one of these green hunks of ice in 1988, near the Amery Ice Shelf, East Antarctic. Most glacial ice occurs in shades of white to brilliant blue. The bluer the ice, the older it is. Typically, compression (压缩)from accumulating layers of snow pushes air bubbles out of the ice, reducing the scattering of white light. The compressed ice absorbs most of the light except for blue, creating the blue color seen in the hearts of icebergs and glaciers.
The green ice was similarly bubble-free, and yet it looked green instead of blue. Warren and his team soon found that the green ice came not from glaciers, but from marine ice. That's the ice from the undersides of floating ice shelves.
At first, the team thought that organic material in the marine ice was causing the green color. But further research showed that the green marine ice didn't have a higher — than — usual amount of organic impurities. Now, a new study finds that a different sort of impurity may be the root cause of the green ice. Warren and his colleagues report that the marine ice at the bottom of the Amery Ice Shelf has 500 times more iron than the glacial ice above.
This iron comes from the rocks under the Antarctic Ice Sheet, which are turned into fine powder as glaciers move over them. The icebound iron oxidizes (氧化)as it contacts seawater. The resulting iron oxide particles take on a green color when light scatters through them. When icebergs break off the larger ice shelf, they carry this iron-rich ice with them. It's like taking a package to the post office. The iceberg can deliver this iron into the ocean far away, and then melt and deliver it to other living things that can use it as a nutrient.
1. What's special about the iceberg found by Warren?| A．The iceberg was old. |
| B．The iceberg absorbed blue light. |
| C．The iceberg's heart was pure white. |
| D．The iceberg was bubble-free and green. |
| A．Impurities of marine ice. |
| B．Reflection of green plants. |
| C．Iron dust from marine ice. |
| D．Compression from layers of snow. |
| A．Deliver the package. |
| B．Bring marine life nutrients. |
| C．Oxidize the seawater. |
| D．Break off the large ice shelf. |
| A．A Study About Antarctic |
| B．The Colors of Icebergs |
| C．The Movement of the Icebergs |
| D．The Mystery of the Green Icebergs |
2 . One of the most important creations of science is the invention of the lighthouses. Lighthouses help in a number of activities such as marking of the dangerous coastlines and directing safe entries to the harbours. The following are some famous lighthouses.
The Jeddah Light
It is located in Saudi Arabia. This lighthouse has been constructed very beautifully and adorns a beautiful structure. The Jeddah Light was built in 1990. This lighthouse is considered as the tallest of the world reaching a fine height of around 436 feet.
The Les Eclaireurs Lighthouse
It is addressed as the “lighthouse at the end of the world”. The Les Eclaireurs Lighthouse is located on a small island east of Ushuaia, the southernmost city of the world. This lighthouse was built in 1920 and today it has become a very famous tourist attraction in Argentina. However, visits to this lighthouse can be made only by boat.
The Peggys Point Lighthouse
Lit in 1915, it is an icon and a popular monument of Canada. The Peggys Point Lighthouse has become a major tourist sight and is considered as one of the busiest attractions in the area of Nova Scotia. This lighthouse also fetches you a wonderful scenic drive and visiting here, you can indulge yourself in the beauty of nature.
The Slettnes Lighthouse
It is the northernmost lighthouse that is located on the mainland of Europe and is considered as one of the most famous lighthouses of the world. This lighthouse is mostly considered as the North Cape Light and is the top lighthouse of Europe. The Slettnes Lighthouse firstly began to light in 1905. Though it was highly damaged during the World War Ⅱ by the Germans, yet it was restored and lit again. This lighthouse is very classic as to its looks.
1. Which lighthouse is only accessible by sea?| A．The Peggys Point Lighthouse. | B．The Les Eclaireurs Lighthouse. |
| C．The Jeddah Light. | D．The Slettnes Lighthouse. |
| A．The lighthouse has a very classic appearance. | B．It was lit again after the restoration in 1905. |
| C．It is the best-known lighthouse in the world. | D．Visiting the lighthouse draws you close to nature. |
| A．A scientific journal. | B．A history textbook. | C．A travel magazine. | D．A design handbook. |
3 . Washington, D.C. Bicycle Tours
Cherry Blossom Bike Tour in Washington, D.C.
Duration: 3 hours
This small group bike tour is a fantastic way to see a world-famous cherry trees with beautiful flowers of Washington, D.C. Your guide will provide a history lesson about the trees and the famous monuments where they blossom. Reserve your spot before availability — the cherry blossoms—disappear!
Washington Capital Monuments Bicycle Tour
Duration: 3 hours (4 miles)
Join a guided bike tour and view some of the most popular monuments in Washington, D.C. Explore the monuments and memorials on the National Mall as your guide shares unique facts and history at each stop. Guided tour includes bike, helmet, cookies and bottled water.
Capital City Bike Tour In Washington, D.C.
Duration: 3 hours
Morning or Afternoon, this bike tour is the perfect tour for D. C. newcomers and locals looking to experience Washington, D.C. in a healthy way with minimum effort. Knowledgeable guides will entertain you with the most, interesting stories about Presidents, Congress, memorials, and parks. Comfortable bikes and a smooth tour route(路线) make cycling between the sites fun and relaxing.
Washington Capital Sites at Night Bicycle Tour
Duration: 3 hours (7miles)
Join a small group bike tour for an evening of exploration in the heart of Washington, D.C. Get up close to the monuments and memorials as you bike the sites of Capitol Hill and the National Mall. Frequent stops are made for photo taking as your guide offers unique facts and history. Tour includes bike, helmet, and bottled water. All riders are equipped with reflective vests and safety lights.
1. Which tour do you need to book in advance?| A．Cherry Blossom Bike Tour in Washington, D.C. |
| B．Washington Capital Monuments Bicycle Tour. |
| C．Capital City Bike Tour in Washington. |
| D．Washington Capital Sites at Night Bicycle Tour. |
| A．Meet famous people. | B．Go to a national park. |
| C．Visit well-known museums. | D．Enjoy interesting stories. |
| A．City maps. | B．Cameras. |
| C．Meals. | D．Safety lights. |
