America, unhappily, is bullish on garbage. Our production of refuse, now about 160 million

tons a year, will rise to 193 million tons by the end of the century 【21】______ nothing is done. This growing effluence of affluence, 3.5 pounds a day for every American, is a 【22】______ of our consumer society, 【23】______ watchwords are "convenience", "ready to use" and "throw away". And it has become a major national environmental issue. forcing citizens, 【24】______ officials and private companies to 【25】______ serious thought to rubbish.

The contentious reality is that the 【26】______ cheap and simple solution to trashdumping it in a landfill just beyond the edge of town 【27】______ no longer workable, particularly around major cities. Old dumps, which now get 8% of all garbage, are filling up, end new 【28】______ have become virtually 【29】______ to build with the result of skyrocketing land costs, 【30】______ stringent environmental regulations and shrill public opposition 【31】______ new landfills "in my backyard". "Five years from now," 【32】______ Bruce Waddle. director of the Environmental Protection Agency's municipal-solid-waste program, "we'll have only half the number of landfills operating."

With this grim prospect, new methods are required, all variations on the only four ways available to deal 【33】______ garbage: bury it, burn it, recycle it or don't make as 【34】______ in the first place. What's needed, experts say, is sophisticated 【35】______ fallout, called "integrated waste management" An 【36】______ valuable items are sorted out of the waste stream and turned 【37】______ new products, and the rest are burned cleanly in a furnace that also produces steam to 【38】______ electricity. Only the ash, 【39】______ of the original volume of trash, is then disposed 【40】______ in carefully engineered landfills.

【21】

A．whatever

B．even if

C．whenever

D．if