14. The recycling of municipal solid waste is widely seen as an environmentally preferable alternative to the prevailing practices of incineration and of dumping in landfills. Recycling is profitable, as the recycling programs already in operation demonstrate. A state legislator proposes that communities should therefore be required to adopt recycling and to reach the target of recycling 50 percent of all solid waste within 5 years.
Which of the following, if true, most seriously calls into question the advisability of implementing the proposal?
(A) Existing recycling programs have been voluntary, with citizen participation ranging from 30 percent in some communities to 80 percent in others.
(B) Existing recycling programs have been restricted to that 20 percent of solid waste that, when reprocessed, can match processed raw materials in quality and price.
(C) Existing recycling programs have had recurrent difficulties finding purchasers for their materials usually because of quantities too small to permit cost-effective pickup and transportation.
(D) Some of the materials that can be recycled are the very materials that, when incinerated, produce the least pollution.
(E) Many of the materials that cannot be recycled are also difficult to incinerate.
这题我选C, 可答案是B
16. A new technique for extracting residues of oil from existing oil wells by using lignins, a by-product of papermaking, is profitable provided that oil prices are over 20 dollars a barrel. Since oil prices are rising, investors looking for companies with prospects for rapid growth in profits would be wise to invest in paper manufacturers, whose currently almost worthless by-product will soon be a profit-boosting commodity.
Which of the following, if true, most seriously weakens the argument above?
(A) A small quantity of lignins are currently sold by paper manufacturers to chemical companies, but most of the lignins produced are burnt as waste.
(B) The 20-dollar-a-barrel oil price as a threshold of profitability for using lignins allows for the increased cost of refining crude oil that has been extracted using lignins.
(C) Only one-half to two-thirds of the total oil in a well can be extracted using conventional techniques of pumping and flooding with water.
(D) Petroleum-based substances that can be used as a substitute for lignins in extracting oil are costly and are made from oil, and these substances therefore increase in price as oil increases in price.
(E) The quantity of lignins produced annually in the manufacture of paper is several times larger than the amount that is likely to be useful in the oil industry.
偶选B, 答案是E, 不解,求助于NN们 | 
