Section BDirections: In this part there is a passage followed by some questions or unfinished statements. For each of them there are four choices marked A), B), C) and D). You should decide on the best choice.Across the rich world, well-educated people increasingly work longer than the less-skilled. Some 65% of American men aged 62-74 with a professional degree are in the workforce, compared with 32% of men with only a high-school certificate. This gap is part of a deepening divide between the well-educated well-off and the unskilled poor. Rapid technological advance has raised the incomes of the highly skilled while squeezing those of the unskilled. The consequences, for individuals and society, are profound.The world is facing an astonishing rise in the number of old people, and they will live longer than ever before. Over the next 20 years the global population of those aged 65 or more will almost double, from 600 million to 1.1 billion. The experience of the 20th century, when greater longevity (长寿) translated into more years in retirement rather than more years at work, has persuaded many observers that this shift will lead to slower economic growth, while the swelling ranks of pensioners will create government budget problems.But the notion of a sharp division between the working young and the idle old misses a new trend, the growing gap between the skilled and the unskilled people, whereas older skilled folk are working longer. The divide is most extreme in America, where well-educated baby-boomers (二战后生育高峰期出生的美国人) are putting off retirement while many less-skilled younger people have dropped out of the workforce.Policy is partly responsible. Many European governments have abandoned policies that used to encourage people to retire early. Rising life expectancy (预期寿命), combined with the replacement of generous defined-benefit pension plans with less generous defined-contribution ones, means that even the better-off must work longer to have a comfortable retirement. But the changing nature of work also plays a big role. Pay has risen sharply for the highly educated, and those people continue to reap rich rewards into old age because these days the educated elderly are more productive than the preceding generation. Technological change may well reinforce that shift: the skills that complement computers, from management knowhow to creativity, do not necessarily decline with age.21. What is happening in the workforce in rich countries?