You have to limit your exposure to risky asset classes to a level that allows you to sustain those positions even in the face of terribly adverse market conditions.

你必须把手中持有的风险资产,限制在一个合适的比例水平,并且即使到了最差的市场环境下,你依旧能够承受这些风险资产

耶鲁公开课 - 金融市场课程节选

Tangent means that it has the same slope, it just touches the efficient portfolio frontier for risky assets at one point, and the slope of the efficient portfolio frontier, including the riskless asset, is a straight line that goes through the tangency point, here.

相切意味着斜率相同，它与包含风险资产的有效边界,交与一点，而包含无风险资产的，有效边界，则是一条过切点的直线，切点在这里。

耶鲁公开课 - 金融市场课程节选