The problems about the midpoints of the chords cut by the taper curve are the most critical and difficult in analytic geometry problems.
直线被圆锥曲线截得弦的中点问题，是解析几何的重点和难点。
2
Temperature of needle tips, the puncture spots on skin and midpoints of needles were measured with semi-conductor thermistor digital thermometer.
使用数字测温仪测量针尖、皮肤进针点及二者中点的温度。
3
Similarly, when adjusting the dial to any given factor, we can find a series of midpoints which altogether form a combined, or complex, planetary picture.