填空题 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 6 certain things together. We call it a produced or 7 . 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 8 inside a pan begins as 9 . 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 10 plastics. They hope to find even more ways to use them!