A: The yield curve is a graph illustrating the term structure of bond interest rates. That is, a graph obtained by connecting the yields of all available bonds with different maturities (from shortest to longest) but the same quality. If the short-term interest rate is low, the curve is called positive yield curve. If the short-term interest rate is high, the curve is called negative (reverse) yield curve. If there is almost no difference between short-term interest rate and long-term interest rate, it is called horizontal yield curve. Investors who invest their money in long-term securities take greater risks, so they get higher returns. So most yield curves are positive yield curves. The yield curve has two characteristics: first, it reflects the relationship between interest rate and time period that really exists in the market. Second, it integrates the prices of all varieties (or a representative variety group) in the market, thus reflecting the overall interest rate level of the market. The most common yield curve is the yield curve of national debt, which shows the yield range from three-month national debt to 20-or 30-year long-term national debt. Fixed-income securities analysts pay great attention to studying the yield curve to judge the interest rate trend.