英语专业四级考试听力复习材料：Plastic

　　Plastic
　　We use plastic wrap to protect our foods. We put our garbage in plastic bags or plastic cans. We sit on plastic chairs, play with plastic toys, drink from plastic cups, and wash our hair with shampoo from plastic bottles!
　　Plastic does not grow in nature. It is made by mixing certain things together. We call it a produced or manufactured material. Plastic was first made in the 1860s from plants, such as wood and cotton. That plastic was soft and burned easily.
　　The first modern plastics were made in the 1930s. Most clear plastic starts out as thick, black oil. That plastic coating inside a pan begins as natural gas.
　　Over the years, hundreds of different plastics have been developed. Some are hard and strong. Some are soft and bendable. Some are clear. Some are many-colored. There is a plastic for almost every need. Scientists continue to experiment with plastics. They hope to find even ways to use them!