underlying economy好像应该是指股票市场相对的经济，美国股市相对美国经济，中国股市相对中国经济的意思，这里意思是说如果是在美国，估价和历史趋势以及相对应的经济形势不符合的时候，通常是人们担心所在。

valuations that seem out of step with historical trends (and, in America, the underlying economy) are usually ones to worry about.

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格罗伯力还指出了在美上市中国股票的另一个优点，那就是美国股市比香港股市更有深度且有更灵活的选择，这有助于应对这些股票的波动性。

Groebli also points out that U.S. listings come with another benefit that can help investors deal with their volatility — a far deeper and more active options market than is available in Hong Kong.

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