阅读理解。 People in the past made clay-pottery because they needed it for their lives. They used the pots they made for cooking, storing food, and carrying things from place to place. Pottery was so important to the early culture that scientists now study it to learn more about ancient civilizations. The more advanced the pottery in terms of pictures, materials and making, the more advanced the culture itself. The artisan who makes pottery in North America today use his or her skill and imagination to create items that are beautiful as well as useful, turning something ordinary into something special. The potter uses one of the Earth's most basic materials, clay. Clay can be found almost anywhere. Good pottery clay must be free from all small stones and other hard materials that would make the potting steps difficult. Most North American artisan potters now buy ready-made clay in stores, but some find the clay they need right in the earth, close to where they work. The most important tools potters use are their own hands; however, they also use wooden modeling tools, plain wire, and sponges. Plain wire is used to cut away the finished pot from its vase on the potter's wheel. After a finished pot is dried of all its wet part in the open air, it is placed in a kiln and fired. The first firing hardens the pottery, arid it is then ready to be glazed and fired again. For areas where they do not want any glaze, such as the bottom of the pot, artisans paint on melted wax that will later bum off in the kiln. They then pour on the liquid glaze and let it run over the clay surface, making any kind of designs that they want. 1. What does the passage mainly discuss? A. Different kinds of clay B. The training of an artisan C. The making of pottery D. The lives of people in the past 2. The word 'it' in paragraph 1 refers to . A. clay B. pottery C. lives D. culture 3. According to the passage, how do most North American potters today get the clay they need? A. They buy it. B. They make it. C. They dig it from the earth. D. They exchange for it. 4. According to the author, what do potters use to remove the pot from the wheel? A. Melted wax B. A plain wire C. potters own fingers D. fire 5. Which material is NOT used in the process of making a good pottery? A.clay B. water C. kiln D. paint