3 . Chugach State Park

Chugach State Park is the largest urban park in theworld, spanning more than 200,000 hectares. In fact, it is almost ten times as large as Table Mountain National Park, the world’s second-largest. Chugach State Park is located in Anchorage, Alaska. The park itself contains various different geographical features, including tall mountains, foothills, lakes, and rivers. It also includes hiking trails that are very popular with tourists.

Pedra Branca State Park

It is an urban park spanning 12,394 hectares in one of Brazil’s largest cities, Rio de Janeiro. It can more accurately be described as an urban forest. The park protects half of what is known as the Atlantic Forest remnant of Rio de Janeiro. It contains more than 900 species of plants and almost 500 different species of birds, mammals, reptiles, and fish.

Margalla Hills National Park

The third-biggest urban park in the world, consisting of 17,386 hectares, is located in the city of Islamabad, which is the capital of the South Asian nation of Pakistan. The park was established in 1980. The park boasts several species of birds, reptiles, and mammals, and it is an extension of the Islamabad wildlife sanctuary. It also includes several hiking trails that are popular with tourists and locals.

Bukhansan National Park

It is located in Seoul, the capital of South Korea. The park itself, which has an area of 7,992 hectares, has been designated by the Guinness Book of World Records as the “Most Visited National Park per Unit Area,” and is visited by an estimated 5 million people a year. It is very popular with hikers and contains Buddhist temples. The park is also home to around 3, 100 animal species.

1. What do we know about Table Mountain National Park?

A．It is located in the US.	B．It is the largest urban park.
C．It has an area of 20,000 hectares or so.	D．It’s the most famous for its different species.

2. Which is your best choice if you are interested in studying varieties of plants?

A．Chugach State Park.	B．Pedra Branca State Park.
C．Bukhansan National Park.	D．Margalla Hills National Park.

3. What do Margalla Hills National Park and Bukhansan National Park have in common?

A．Both of them lie in Asia.

B．Both of them are of the same size.

C．Both of them are especially popular with foreigners.

D．Both of them are home to endangered animal species.

4 . 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.

2. What's the actual reason for the green color of some Antarctic icebergs?

A．Impurities of marine ice.

B．Reflection of green plants.

C．Iron dust from marine ice.

D．Compression from layers of snow.

3. What's the function of the iron mentioned in the last paragraph?

A．Deliver the package.

B．Bring marine life nutrients.

C．Oxidize the seawater.

D．Break off the large ice shelf.

4. What can be a suitable title for the text?

A．A Study About Antarctic

B．The Colors of Icebergs

C．The Movement of the Icebergs

D．The Mystery of the Green Icebergs