单项选择题

Is this any way to plan for retirement After a week of huge swings, the Standard ＆ Poor’s 500-stock index, a broad assess of the market, was modestly higher on Friday but still down for the week.
On Monday, the market plunged; on Tuesday, it roared back, only to drop sharply again on Wednesday before soaring on Thursday. As The Times’s Floyd Norris and Christine Hauser pointed out on Friday, never before in the history of the S. ＆ P. 500, which dates back to 1928, had there been four alternating days of losses and gains of more than 4 percent.
There have only been two times since the Great Depression when the index has moved at least 4 percent in four straight trading sessions—in October 1987, when the market crashed, and in November 2008, during some of the darkest days of the financial crisis. Those are not exactly moments in stock market history that inspire investor confidence.
For individual investors, whose ability to retire depends on stock investments in 401 (k) ’s and other retirement plans, recent swoons (疲软) are yet another hit. If a worker had invested entirely in stocks, retirement might still be a very long way off.
The results would be better if an investor had a retirement portfolio (投资组合) evenly divided between stocks and bonds—a 5.5 percent gain from the peak in 2007 to the close on Friday. For policy makers, the changeful week is yet another moment to reconsider the risks in 401 (k) ’s and the need to make retirement savings safer. One of the thorniest problems is that even someone who steadily contributes to a 401 (k) and makes sensible investments can still end up with too little, depending solely on whether markets are up or down as retirement nears.
There needs to be a way to ensure that a lifetime of savings cannot be undermined by forces beyond one’s control. Alicia Munnell, director of the Center for Retirement Research at Boston College, has an idea that deserves more study and debate: a new type of savings account—in addition to Social Security and 401 (k)’s—that would spread the risks among workers, retirees and government.
One thing is sure. Having each individual bear all of the investing risk is not the road to a secure retirement.
If a worker puts all his money into stock market, he will ______.