Nowadays, lots of foreigners are learning Chinese. Like many of them, I 1 knew two words of Chinese ("Ni Hao" and "Xie Xie") when I first came to Beijing, China in 2009. As you can guess, my life was 2 for a while after I arrived. Simple tasks like ordering food or taking a taxi were quite stressful.

    I knew I had to learn more Chinese, so I 3 a Chinese class. My teacher was 4, although I didn't learn enough to have a real conversation. Later I studied on my own as well, but my progress was still slow. And I decided to 5.

    Around this time, I started playing in a band with a Chinese man who became one of my best friends in Beijing. He taught me a lot of 6 about music, such as "melody". He learned a lot of English from me in return, so it was a good way to 7 language and culture.

    I have learned enough Chinese to 8 many problems like booking train tickets. These days, there are more foreigners who are studying Chinese. I can 9 why it's an amazing language. Finally, I found that the best way to learn a 10 is to make friends with native speakers and spend time with them.

    On July 20, 1969, Neil Armstrong became the first person to walk on the moon. The space suit Armstrong wore on his lunar mission has come to symbolize courage and human achievement. In 1971, the Smithsonian's National Air and Space Museum(NASM), in Washington, D.C., acquired (获得) Armstrong's suit. It stood proudly on display for visitors to admire, until there were changes in the suit's appearance. "Over time, the suit started to show signs of deterioration," Lisa Young said. Young is an objects conservator (文物修复员) at NASM. It is her job to preserve(维护)historical and cultural objects.

    "Plastics are tricky to conserve," Young says. They tend to degrade (降解)over time. Neoprene is one type of plastic in Armstrong's suit. The material can turn brittle and break into tiny pieces. This would ruin the space suit. NASM, seeking ways to preserve this historical treasure, removed it from display in 2006.

    What causes plastic to degrade in the first place? "Many things," Odile Madden says. Madden is a scientist in California. She explains that sunlight, water, humidity, and dust can cause plastics to degrade. "Some plastics will break down no matter what we do," Madden says.

    Yet history can still be saved. Scientists have found that storing plastics in cooler temperatures, with lower humidity levels, can slow degradation. Young says Armstrong's suit is currently in storage at a temperature of 63°F and a lower relative humidity of 30%. These conditions will be maintained when Armstrong's suit returns to a museum display case in time for the 50^th anniversary of the moon landing.

    Plastic degradation affects art, too. Artist Claes Oldenburg created False Food Selection in 1966.It consists of plastic food displayed in a wooden box. The plastic food used to look real. Now, some of it has flattened and yellowed. Georgina Rayner is a conservation scientist at Harvard Art Museums, in Cambridge. She says the artwork's wooden box produces an acidic (酸的) gas that eats away at the plastic. This speeds up the degradation process. But Rayner is motivated to conserve this artwork and others like it. "Plastics are a part of our history," she says. "It's important to preserve them so that future generations can understand the journey we've taken."

    What will man be like in the future-in 5. 000 or even 50, 000 years from now？We can only make a guess, of course, but we can be sure that he will be different from what he is today. For man is slowly changing all the time. Now look at the chart below, and you'll find some differences.

    Perhaps all this gives the impression that future man will not be a very attractive creature(生物) to look at！This may well be true. All the same, in spite of all these changes, future man will still have a lot in common with us. He will still be a human being, with thoughts and emotions(情感) similar to our owns.