Aging poses a serious challenge to OECD(Organization of Economic Co-operation and Development)countries，in particular，how to pay for future public pension liabilities. And early retirement places an__1__burden on pension financing. There is no easy solution，but__2__retirement could help.

　　Early retirement may seem like a worthy individual goal，but it is a socially__3__one，and makes the present public pension system difficult to sustain for long. The__4__reason is that more people are retiring early and living longer. That means more retirees depending on the__5__of those in work for their income. The__6__is worrying. In the next 50 years，low fertility rates and__7__life expectancy in OECD countries will cause this old-age dependency rate to roughly double__8__size. Public pension payments，which afford 30-80% of total retirement incomes in OECD countries，are__9__to rise，on average，by over three percentage points in GDP and by as much as eight percentage points in some countries.__10__is the pressure on pension funds that there is a danger of today‘s workers not getting the pensions they expected or felt they__11__for.

　　Action is needed，__12__simply aiming to reduce the__13__(and cost)of public pensions，or trying to__14__the role of privately funded pensions within the system，though necessary steps，may be__15__to deal with the dependency challenge. After years of__16__early retirement schemes to avoid__17__and higher unemployment，many governments are now looking__18__persuading people to stay in work until they are older. Surely，the thinking goes，if we are healthier now and jobs are physically less__19__and unemployment is down，then perhaps the__20__rate should rise anew.

　　1.[A] unsolvable [B] additional [C] unsustainable [D] undue

　　2.[A] delaying [B] retaining [C] detaining [D] hindering

　　3.[A] ultimate [B] unattainable [C] specific [D] expensive

　　4.[A] substantial [B] essential [C] potential [D] controversial

　　5.[A] donating [B] sponsoring [C] subsidizing [D] funding

　　6.[A] outlook [B] outcome [C] outbreak [D] outset

　　7.[A] prolonging [B] expanding [C] soaring [D] rising

　　8.[A] in [B] on [C] by [D] for

　　9.[A] conceived [B] reckoned [C] expected [D] meant

　　10.[A] As [B] Such [C] So [D] It

　　11.[A] should pay [B] paying [C] be paid [D] would pay

　　12.[A] but [B] for [C] and [D] thus

　　13.[A] multitude [B] implementation [C] application [D] generosity

　　14.[A] exaggerate [B] augment [C] magnify [D] multiply

　　15.[A] insufficient [B] influential [C] inefficient [D] intrinsic

　　16.[A] advancing [B] previous [C] ahead [D] preceding

　　17.[A] suspensions [B] abundances [C] redundancies [D] discrepancies

　　18.[A] for [B] to [C] about [D] at

　　19.[A] turbulent [B] strenuous [C] compact [D] intricate

　　20.[A] dependency [B] fertility [C] present [D] mortality