What does it mean to be green? "Green" is more than just a color. It also means taking special steps to protect the environment. Why green? Plants are green, and without them, the earth wouldn't be such a lovely home for us.

     Every day, people make a lot of trash and pollution. What can you do? Here's a four-step guide to being green:

       Reduce the amount of things you use and throw away.

      When you use less of something, you do a good thing for the earth. For example, if you take a shorter shower, it means that you will use less water and less fuel(燃料).

      Reuse things when you can.

      Sometimes people call our society a "throwaway society". That means that we're quite used to throwing away old things and buying new things. Many times, even if you no longer need something, someone else just might need it. For example, if you are in Grade Two, why don't you give your used books to a student who is in Grade One now?

      Recycle bottles, paper, books and even toys.

      Recycling is easy. Many people will pick up your recycled things right in front of your house. Tell your mom or dad that you want to recycle things and help remind others about which things can be washed and recycled.

      Enjoy the earth--walk in the woods, plant a tree, and eat some of the delicious food that it produces.

为了观察狗的甲状腺机能亢进引发的症状，可以采取的措施是(    )

读图，完成下列各题。：

（﹣b）²•（﹣b）³•（﹣b）⁵=____。