Unit 6 When was it invented Section A 1a -2c 课件2023-2024学年人教版九年级英语全册

Unit 6 When was it invented? Section A(1a-2c) Scientistsin Britain and the United Sates have made a new kind of enzyme(酵素) that eats plastics(塑料).With its help,plastics can be turned into smaller parts and go away quickly.Scientists believe that,in the future,it could solve the problem of plastic pollution. The enzyme is able to break down PET,a form of plastic.PET was first made in the 1940s and is now widely used to make plastic bottles.It can remain in the environment for many years and pollute large areas of land and water.So it has always been a headache to deal with the waste from PET and other plastics. The researchers made the discovery(发现) while examining the structure of a natural enzyme in Japan. They found that the natural enzyme was helping to break down PET plastics.So, they decided to make small changes to the enzyme by adding some amino acids (氨基酸).It made the natural enzyme's plastic-eating ablilities work faster and better. John McGeehan,one of the lead researchers,said,“We've made an improved enzyme. It's better than the natural one.And we are trying to make more improvements to it.”He went on,“The enzyme is not harmful to humans or animals,and it is friendly to the environment. So we are considering putting it into wider use.” The team is now trying to make the enzyme break down PET in large quantities(大量地). “We'll see that the plastic pollution may be stopped with this technology.However,there is still a long way to go,”John McGeehan added. Sustained SilentReading Lead in What are they? What are they made of? What invented sky lantern? They are sky lanterns. They are made of bamboo. Zhuge Kongming invented it. Sky lantern was invented by Zhuge Kongming. What was…invented? It was invented in… Who invented it? It was invented …. 1885 Benz 1876 Bell In pairs: …was invented before/after… When were they invented? Which do you think was invented first? Was the telephone invented before the TV? Look at the things below. In what ord