1. But even the mosquito has been subdued by attention to drainage and by chemical sprays.
    然而即使蚊子，也由于我们注意清理污水和喷洒化学药品就被制服了。

2. The waste of this chemical factory contaminates the environment.
    这家化工厂的废物污染了环境。

3. The chemical formula for salt is NaCl.
    盐的化学分子式是NaCl.

4. There are thirty microscopes in our chemical laboratory.
    我们的化学实验室里有三十台显微镜。

5. This applies particularly to chemical industries, where chance discoveries play a much larger part than they do in physical and mechanical industries.
    在这化学工业方面尤为突出。同物理和机械工业相比，化学工业中偶然发现的机会要多得多。

6. The paper-making process uses large amounts of water, burns fossil fuels and produces much chemical waste.
    因为造纸工艺要用去大量的水，燃烧大量的矿物燃料，而且还会产生大量的化学废料。

7. He is majoring in chemical engineering.
    他正主修化学工程。

8. He is a famous chemical expert.
    他是一位出名的化学专家。

9. During a single crucial three-week period during our teenage years, chemical activity in the brain is cut in half.
    我们的青少年阶段有一个为期三周的关键时期，此时脑部的化学反应活动一分为二。

10. A chemical changetakes place in paper when it burns.
    纸燃烧时产生化学反应.