2021年下半年英语四级考试时间为12月18日,文都四六级为大家整理了2021年12月英语四级听力50篇,希望可以为大家带来帮助,预祝大家通过大学英语四级考试。

07 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!

【责任编辑:Xiaoxu】