题型:阅读选择 题类:模拟题 难易度:普通
广西北部湾经济区六市同城学科2019届九年级英语素养测试试卷
Bioplastic(生物塑料) is a kind of plastic, but it is not the same as normal plastic. Normal plastic is made from chemical materials and takes a very long time to degrade(降解). But bioplastic is good for the environment. It is made by using bacteria(细菌) to process(加工) natural sources like vegetable oils, corn or sugar. It can degrade more easily.
But there is a problem with bioplastic. The "food" that bacteria eat is what we eat. This means that bacteria are competing against humans for the same resources.
Now scientists have found a new way to make bioplastic——using two kinds of bacteria and sunlight, according to Newsweek.
One of the bacteria can use sunlight to produce sugar. The other kind lives in the salty waters of Bolivia. It eats the sugar that the first bacteria produce and then it can produce polymers(聚合物). Polymers are used to create bioplastics. The way the bacteria store polymers is similar as humans store fats.
The new way to produce bioplastic has many advantages. It is 20 times faster than the normal way we produce bioplastic. Moreover, using these two bacteria saves resources.
Firstly, producing a lot of bioplastic requires corn and sugar, which are used to feed normal bacteria. And growing corn and sugar needs farmland. But these two bacteria can just use sunlight. The land that is saved can be used to grow food for humans. Besides, this system doesn't need rich land or clean water at all, scientists said to Newsweek.
The next problem scientists face is that they want to put their lab research into real-world practice. By doing this, bioplastic made with these two bacteria can be widely produced in the future.
a. eating the sugar b. creating bioplastics
c. producing polymers d. using sunlight to produce sugar
Parents today also worry about their children's diets. Some doctors give the following advice:
Teenagers shouldn't eat too much junk food. Teenagers shouldn't eat food with too much salt. Salt can cause high blood pressure in the future. Teenagers should eat food with less fat, oil and sugar. Teenagers need to eat some fruits and vegetables every day. Fruits and vegetables are rich in vitamins and have little fat. Teenagers need to drink more milk. Milk will help their bones grow. Teenagers need to eat breakfast every day. This is good for their bodies and minds. |
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