DNA is the whole “map”of the human body. It is something that all humans have, and it tells the body what to do. DNA is the reason that we look like our parents, because we get some of their DNA to make our own.
     People have been trying to understand the human body for a long time. In 1860, Mr. Mendel discovered why we look the same as other people in our family. It is because of small things called “genes(基因)” in our body. In 1953, two scientists, Watson and Crick, found out that those small parts are really messages. They're written in the DNA with a special language.
    In 1961, another two scientists found the first “word”that could understand in that language. It shows how DNA tells the cell (细胞) to build its parts. So far, scientists have found all the words in the DNA map, but we still do not understand what they all do. By understanding what just one “word”means, we can help to save people from several illnesses. So the more we understand. The more doctors will be able to do.
      Most people hope that this will help to make better medicine and help sick people. Other people worry that when we learn more “words”and find out more information, we will use it in the wrong way, just to make people more attractive(有吸引力的) , or stop sick people getting jobs.

金九皋，节水志愿者，马桶节水器的发明人。利用他研制的抽水马桶节水器，一次用水量仅为原来的1/5。曾有企业愿出高价购买节水器专利，被金九皋拒绝。他向街坊四邻、亲戚朋友义务上门安装节水器。多年来，金九皋及团队培训了万余名节水志愿者，为数万人传授节水经验。如今，朝阳区6000多户家庭已采用了此项发明，年节水40多万吨，节约费用200多万元。为此他被评为2014年度“北京榜样”，由此可见（  ）