Read the following text and fill each of the numbered spaces with ONE suitable word.

　　Write your answers on ANSWER SHEET l.

　　Pollution is a“dirty”word.To pollute means to contaminate-topsoil or something by introducing impurities which make(31) ___unfit or unclean to use.Pollution comes in many forms.We see it，smell it，(32) ___it，drink it，and stumble through it.We literally lived in and breathe pollution，and(33) ___surprisingly，it is beginning to(34) ___our health，our happiness，and our civilization.

　　Once we thought of pollution(35) ___meaning simply the smog--the choking，stinging，dirty(36) ___that hovers over cities.But air pollution，while it is(37) ___the most dangerous，is only one type of contamination among several(38) ___attack the most basic life functions.

　　Through the uncontrolled use of insecticides，man has polluted the land，(39) ___the wildlife.By(40) ___sewage and chemicals into rivers and lakes，we have contaminated our(41) ___water.We are polluting the oceans，too，killing the fish and(42) ___depriving ourselves(43) ___an invaluable food supply.

　　Part of the problem is our exploding(44) ___.More and more people are producing more wastes.But this problem is intensified by our“throw—away”technology.Each year Americans(45) ___of 7 million autos，20 million tons of waste paper，25 million pounds of toothhpaste tubes and 48 million cans.We throw away gum wrappers，newspapers，and paper plates.It is no longer wise to(46) ___anything.Today almost everything is disposable. (47) ___of repairing a toaster or a radi0，it is easier and cheaper to buy another one and discard the old，even(48) ___95 percent of its parts may still be functioning.Baby diapers，which used to be made of reusable cloth，are now paper throw-aways.Soon we will wear clothing made of(49) ___：“Wear it once and throw it away”will be the slogan of the fashionable consciousness.

　　Where is this all to end? Are we turning the world into a gigantic dump，or is there hope that we can solve the pollution problem?(50) ___，solutions are in sight.A few of them are positively ingenious.