I have it shown with the--the vertical lines on this chart indicate recessions and this shows--this is from 1948 to 2007 and every recession that we've had since 1948 is shown.

我用图中的这些垂直的线表示,从1948年至2007年的经济衰退,从1948年以来的每一次衰退

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They determine this by looking at a complex set of lines overlaid onto a stock chart, such as moving averages, support lines, volume activity, etc.

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Here is the chart and some indicative lines.

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The blue lines on the chart above represent the Bollinger bands, and below the bar chart, I have plotted the band width indicator.

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