将燃着的小木条神人正放在桌上的装满氧气的集气瓶中，观察到小木条燃烧的更旺，说明氧气具有的性质是：

（1）____．

（2） ____

      Everyone likes living in a clean and comfortable environment. If the envionment(环境) is bad, it will affect（影响）our bodies, and make us not feel well. Sometimes we may be terribly ill. At that time we don't want to work, and we have to stay in bed and rest at home. So the envrionment is very important to us.
      It's germ that makes us ill. There are germs everywhere, They are very small and you can't find them with your own eyes, but you can see them with a microscope（显微镜）. They are very small and there may be hundreds of them on a very small thing, Germs can always be found in the dirty water. When we look at dirty water under the microscope, we shall see them in it. Germs can also be found in air and dust（灰尘）. If you cut your finger, some of the dust from the floor may go into it, and you will have much pain in it. Sometimes the germs will go into all of your boby, and you will have pain everywhere.
     To keep us healthy, we should try to our best to make our environment become cleaner and tidier. This needs us to act together.