Pinpointing the start of the U.S. recession may take months. One common definition -- two straight quarters of declining economic output -- is likely to be met in the fourth quarter.

• 也许要几个月之后才能确定下来美国本轮经济衰退始于何时。不过如果用经济产出连续两个季度下滑这一常用指标来衡量，美国经济第四季度或许就将陷入衰退。