3．Why did Terri Olsen write this letter?

　　A．To ask students to care for the plants.

　　B．To try to make the school more beautiful.

　　C．To advise students to visit Natural Springs.

　　D．To draw the headteacher's attention to nature.

　　解析：选B　写作意图题。由第一段中的"we cannot turn our school into such a garden, we can surely add more beauty to its surroundings"以及下文的相关信息可知，作者通过此信旨在说服校长同意自己的建议，即：通过举办植物交换活动给自己的学校引进更多植物来美化校园，故选B项。

　　B

　　When you hear the name Greenland, you might think of a place with warm weather and lots of leafy forests. In reality, about 80 percent of this Arctic island is covered by a sheet of ice - and now that ice is melting fast. As a result, NASA has sent a robot to help save the island's ice.

　　To determine how to do that, scientists need to learn more about how and why Greenland's ice sheet is changing. But sending human researchers to study the ice sheet on snowmobiles and in aircraft can be expensive and time­consuming.

　　So a group of college students at a NASA engineering summer camp came up with an alternative. They invented a robot known as GROVER. On May 3, NASA sent GROVER to Greenland to begin gathering data on the changes that the ice sheet is undergoing.

　　Last summer alone, more than 97 percent of Greenland's icy surface experienced some melting. Some scientists predict that in 2,000 years, the entire ice sheet will be one big puddle (水坑) because of rising temperatures in the region. That's bad news. If the ice sheet completely melts, sea levels will rise. Rising sea levels around the world could bring about severe flooding, and some small islands could even disappear beneath the waves.

　　That's why, during the next month, GROVER will travel for more than 400 miles over the ice sheet. GROVER will be able to work longer and gather more data than any scientist on a snowmobile could. The 6­foot­tall, 800­pound robot is powered by solar energy. It will be able to run anytime throughout the day or night because the sun never sets below the horizon (地平线) during the Arctic summer.

　　"Robots like GROVER will give us a new tool for glaciology (冰川学) studies，" says NASA glaciologist Lora Koenig.

　　Scientists hope this is just the beginning for GROVER. If the robot completes its first test, NASA plans to send GROVER out to explore the ice sheet for many months at a time.

语篇解读：本文是说明文。文章主要报道了格陵兰岛冰川面临的严峻形势及NASA为此采取的措施。