More recent research suggested that those gains are the same whether you exercise for short periods over five days or longer sessions over two or three days.

VOA: special.2010.06.08

Listen, the two periods in American history 1945 1890 to 1945 The economy suffers 3 contractions of 5 percent, 15% 2 of 10, and 2 of almost 15 percent.

听好，美国历史上的两大时期,第一时期是从1890到5,经济遭受过三次紧缩率为5%的经济紧缩，两次10%，还有两次高达。

斯坦福公开课 - 经济学课程节选

We had the impeachment of President Clinton, we had the Vietnam War, we had the Iran-Contra investigation, periods when the two parties had an enormously high level of tension.

VOA: special.2011.01.10

that tell about life in America during two different periods.

VOA: special.2009.03.23