阅读下列短文，从每题所给的A、B、C和D四个选项中，选出最佳选项。
A
Four Trips to Get Children Out and About
The Inner Mongolia autonomous region takes up 12.3 percent of China’s land area and spans the northeastern, northern and northwestern parts of the country. There are abundant forests, grasslands and rich ethnic traditions. Here are some recommended routes.
Modern prairie（大草原）
Travelers can sample Mongolian culture and history at the Inner Mongolia Museum and watch local dairy production at the Yili Industrial Park in Hohhot, the region’s capital. Children can experience leather painting and make cheese at the Mengliang Ethnic Handicraft Park in the city.
Nature
Hulunbuir city’s Nuogan Lake offers bird-watching and pastoral（田园的）landscapes. Children can learn how to identify rare vegetation and animals at Arxan National Forest Park in Hinggan League, where the volcanic landscape is another highlight. Classes on how the natural hot springs were formed are also available in Arxan.
Geology and folk customs
Fun desert treks (徒步旅行) are available at the Yulong Sand Lake in Chifeng city, where lecturers are on hand to give classes on observing and mapping the stars. Children can later visit the stone forest at Hexigten, which was formed by glaciers during the Quaternary period. Classes on local geology are given to help children appreciate the area’s nature. The spruce (云杉) zone in Chifeng’s Baiyin Obo National Nature Reserve highlights the importance of nature conservation through the study of the endangered Mongolian spruce.
Desert
Travelers sail in boats on Wuhai city’s Wuhai Lake, where patches of desert encroach（侵蚀）into the waterside landscape. Sand surfing classes are offered at Jinsha Bay in Wuhai. Tree-planting sessions are prepared for children to help them get involved in environmental protection at Alxa League. Children can also go out to hike and camp in Alxa’s Tengger Desert to learn survival skills in the wilderness.
21. What can children do at the Mengliang Ethnic Handicraft Park?
A. Observe rare animals. B. Enjoy leather painting.
C. Identify different stars. D. Learn sand surfing.
22. Where can children learn about the formation of the natural hot springs?
A. At Arxan National Forest Park. B. At Yili Industrial Park.
C. At Yulong Sand Lake. D. At Wuhai Lake.
23. Why are there tree-planting sessions for children?
A. To show them some beautiful birds. B. To help them appreciate nature.
C. To inspire them to protect the environment. D. To teach them survival skills.
