Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks from 31 to 35.

Water is one of our most precious resources; to (31)_______ it simply, without water there would be no life. Unfortunately, many of us seem to have forgotten this fact, and as a result the world is facing the danger of running out of water. The actual amount of water on earth has changed (32)_______since the time of dinosaurs. The problem has been caused by people's misuse of our water supply. This not only means that we have polluted our rivers and seas, but also that we are (33)_______ a great deal of this precious resource. Unfortunately, the destruction of the rain forests has made this problem worse since much of the rain (34)_______falls is lost because it runs off into the sea. The population of the earth is increasing daily, (35)______it is vital that we find a solution to this problem before it is too late.