四、英语阅读理解题 阅读下列短文，从每题给出的四个选项中，选出最佳答案。 Cigarette smoking is a health hazard of sufficient importance in the United States. It was 50 years ago this month that America's Surgeon General sounded that warning, marking the beginning of the end of cigarette manufacturing—and of smoking itself—as a respectable activity. Some 20 million Americans have died from the habit since then. But advertising restrictions and smoking bans have had their effect: the proportion of American adults who smoke has dropped from 43% to 18%; smoking rates among teenagers are at a record low. In many other countries the trends are similar. The current Surgeon General, Boris Lushniak, marked the half-century with a report on January 17th, declaring smoking even deadlier than previously thought. He added diabetes, colorectal cancer and other ailments to the list of ills it causes, and promised end-game strategies to extinguish cigarettes altogether. New technologies such as e-cigarettes promise to deliver nicotine less riskily. E-cigarettesgive users a hit of vapour infused with nicotine. In America, sales of the manufacturer, who is the fastest e-cigarettes-adopter, have jumped from nearly nothing five years ago to at least 1 billion in 2013. At first, it looked as if e-cigarettes might lure smokers from the big tobacco brands to startups such as N JOY. But tobacco companies have bigger war chests, more knowledge of smokers' habits and better ties to distributors than the newcomers. Some experts reckon Americans will puff more e-cigarettes than normal ones within a decade, but tobacco folk are skeptical. E-cigarettes account for just 1% of America's cigarette market. In Europe 7% of smokers had tried e-cigarettes by 2012 but only 1% kept them up. And no one knows what sort of restrictions regulators will eventually place on reduced risk products, including e-cigarettes. If these companies can manage the transition to less harmful smokes, and convince regulators to be sensible, the tobacco giants could keep up the sort of performance that has made their shares such a fine investment over the years. But some analysts are not so sure. Many tobacco firms are struggling to deliver the consistency of the earnings-per-share model we've seen in the past. If that persists, investors may fall out of love with the industry. A half-century after the Surgeon General's alarm, they, and hopeless smokers, are its last remaining friends. 请回答问题。
1. It can be learned from Paragraph 1 that cigarette manufacturing in the United States ______.
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