41.  He called for everyone in the town to protect the nature.

42.  People made a rule to protect the nature.

43.  We believe we can make the earth to be a heaven as long as each of us can protect the water!

44.  In a word, please save every drop of water in order to protect our beautiful earth.

45.  We must protect fresh water in order to survive in the earth.

46.  Let's take actions from now on to protect our fresh water resource for the future.

47.  It should be protected carefully.

48.  We all have duty to protect water.

49.  All in all we should try our best to protect the fresh water rather than devoice it.

50.  First, we should realize this point; Second, we ought to make good use of freash water; Third, we should protect freash water from being polluted; Finaly , we can get freash water from sea-water with the help of modern science.