1.CAUTION: Tangency between cylinders occurs at the center plane of the cylinders only if the cylinders are of equal diameter .
仅当两个圆柱孔直径相等时，相切发生在圆柱中心平面。
2.tangency is controlled by the first two control points from a surface boundary , assuming that these points lie in one line.
相切是由曲面边界的最初两个控制点控制的（假设这些点在一条线上）。
3.Moon enters penumbra: Instant of first external tangency of Moon with the penumbra.
半影食始：月球刚刚和半影接触，这时肉眼觉察不到。
4.Then everyone should be holding the tangency portfolio.
所有人都应该持有切线投资组合
5.the tangency portfolio gives rise to what's called the mutual fund theorem in finance.
切线投资组合引申出金融学里的共同基金定理。
6.Moon enters umbra: Instant of first external tangency of Moon with the umbra.
初亏：月球由东缘慢慢进入地影，月球与地球本影第一次外切。
7.assumes everyone is rational and holds the tangency portfolio.
假设每人是理性的并持有切线资产组合
8.is a straight line that goes through the tangency point, here.
则是一条过切点的直线切点在这里
9.accurately, such as minuteness, more deformable that unfit for tangency measurement. This method has a wide application foreground.
此种测量方法非常适合于微小、易形变等接触测量难以准确测量的机械零件的参数检测，具有广阔的应用前景。
10.Moon leaves penumbra: Instant of last external tangency of the Moon with the penumbra.
半影食终：月球离开半影，整个月食过程正式完结。